Multiple power strips

The easiest thing of course would be to leave it as it is.

Don, two things to consider with your question.  Are any of the power strips of the surge protector variety?  If so, and you want that protection to work correctly, then daisy chaining them one to the next [EDIT can defeat their surge protections may or might not cause some issues (see reply below for clarification)].  In which case, each surge protected power strip should be plugged into either an outlet, heavy duty extension chord (12 Gauge is good for 15 Amps at 100'), or a non-surge protected power strip.

The other thing to consider is that these power strips are typically rated for 15 Amps.  The total load of everything connected to the first in your string of power strips should not exceed 15 Amps @120VAC (including the additional strips that might be plugged into it).

I would also suggest using power strips with built-in circuit breakers, especially the first one in the chain.  But ultimately, the safest thing is to not daisy chain them as there's too much that could go wrong.

Although a bit more expensive, plugging everything into either a GFCI circuit/outlet or a power strip with built-in GFCI will provide an added measure of human safety protection against shock hazards on and around the layout and display.

Our tiny town has a volunteer fire department that answers between 150 and 200 calls a year. Around three or four of them are working structure fires, usually suppressed in the first few minutes with minimum damage.

The last three of those fires were caused by multiple power strips plugged in a daisy-chain configuration. 

As a fire marshal, a volunteer fire fighter, and an electrician, I would respectfully suggest that you determine what total electrical load is required for your assemblage of buildings and lights, and using that calculation, obtain a power supply, controlled by one master switch, whose output can be spilt among the various loads, and wired in a safe manner via industry standard terminal strips, with individual fusing.

Just don't plug a space heater into the last one.

OMG!  Thanks Rob

@SteveH posted:

Don, two things to consider with your question.  Are any of the power strips of the surge protector variety?  If so, and you want that protection to work correctly, then daisy chaining them one to the next can defeat their surge protections.  In which case, each surge protected power strip should be plugged into either an outlet, heavy duty extension chord (12 Gauge is good for 15 Amps at 100'), or a non-surge protected power strip.

I don't see how this can happen.  The power strip almost surely has one or more MOV devices to provide the surge protection.  Having more than one MOV across the line surely isn't going to lessen the surge protection.  Most power strips also include a circuit breaker, and putting those in series won't affect their function either.

The other thing to consider is that these power strips are typically rated for 15 Amps.  The total load of everything connected to the first in your string of power strips should not exceed 15 Amps @120VAC (including the additional strips that might be plugged into it).

This certainly makes sense, and I believe the OP had this covered in his description of the usage.

"The power strip almost surely has one or more MOV devices to provide the surge protection. "

The cheap ones don't have those features. Take one apart and you'll find the flimsiest metal contacts and the cheapest plastic assemblies. The real cheap ones have a red power switch that resembles a switch with a pilot lamp, but, no surprise, there is no lamp in the switch.

@gunrunnerjohn posted:

I don't see how this can happen.  The power strip almost surely has one or more MOV devices to provide the surge protection.  Having more than one MOV across the line surely isn't going to lessen the surge protection.  Most power strips also include a circuit breaker, and putting those in series won't affect their function either.

John, I had read in a few places on the web that different designs of surge protectors if daisy chained could essentially counteract each other if connected in series (daisy chained).  After you questioned this assertion, I did some more reading and could find little sound reasoning to back up my earlier statement you questioned with anything conclusive.  There is one thread I found that does describe in some detail how daisy chaining surge protectors can add excessive noise to the line.

If you'd be interested in reading the thread, the salient information begins about halfway down the page with "backhoe" 's first post and concludes with the last post by "jaywallen"

https://arstechnica.com/civis/viewtopic.php?t=1029064

@Arthur P. Bloom posted:

Our tiny town has a volunteer fire department that answers between 150 and 200 calls a year. Around three or four of them are working structure fires, usually suppressed in the first few minutes with minimum damage.

The last three of those fires were caused by multiple power strips plugged in a daisy-chain configuration.

As a fire marshal, a volunteer fire fighter, and an electrician, I would respectfully suggest that you determine what total electrical load is required for your assemblage of buildings and lights, and using that calculation, obtain a power supply, controlled by one master switch, whose output can be spilt among the various loads, and wired in a safe manner via industry standard terminal strips, with individual fusing.

I'm with Arthur on this one. I run the Facilities Management department for a University in New York State, and am also a licensed master electrician. I've seen my share of cooked plugs and cords over my 30+ year career.

Our State and local fire codes do not permit daisy-chaining power strips. I would avoid this practice completely. It's always best to distribute power loads as best as possible. Always make sure your load does not  exceed the rating of the cord or power strip.

As Steve mentioned, ground-fault and arc-fault devices are excellent options for added safety. Consult a local professional if necessary. Surge protection is fine for protecting electronic equipment, but they do not provide over-current protection.

@Don Baird posted:

My layout has a number of Menards’s structures and Dept 56 buildings on it.

I can reconfigure the wiring so that the second and third strip are separate from the first. To do this I would run a 12 gauge outdoor extension from a different wall outlet across the ceiling and drop it to the layout. This outlet is on a 20 amp fuse. (The transformers are connected  a 15 amp line). The 12 amp extension cords has three outlets. If for some reason it is necessary, I think I can plug both  the second and third into the extension cord instead of one into the other.

what’s the best way to proceed?

Don- The National Electrical Code does not permit extension cords to be run as concealed wiring. You can run the cord and use the other circuit as long as the cord is not concealed. If you can't, then speak to a local electrician to run another permanent outlet for you.

Have you checked the load on the existing 15 A circuit? You may be able to just add another duplex receptacle off of the same circuit.

I'm not personally familiar with Menards buildings but you could look at a large singe power supply to run all of the buildings instead of numerous wall-warts.

Bob

@SteveH posted:

John, I had read in a few places on the web that different designs of surge protectors if daisy chained could essentially counteract each other if connected in series (daisy chained).  After you questioned this assertion, I did some more reading and could find little sound reasoning to back up my earlier statement you questioned with anything conclusive.  There is one thread I found that does describe in some detail how daisy chaining surge protectors can add excessive noise to the line.

If you'd be interested in reading the thread, the salient information begins about halfway down the page with "backhoe" 's first post and concludes with the last post by "jaywallen"

https://arstechnica.com/civis/viewtopic.php?t=1029064

Yep, and I agree generally with what is stated.  While I agree that you can get in trouble with overload daisy-chaining power strips, you can get in trouble overloading one power strip or even one outlet.  I hope these "facts" aren't a revelation!

@RSJB18 posted:

I'm with Arthur on this one. I run the Facilities Management department for a University in New York State, and am also a licensed master electrician. I've seen my share of cooked plugs and cords over my 30+ year career.

Our State and local fire codes do not permit daisy-chaining power strips. I would avoid this practice completely. It's always best to distribute power loads as best as possible. Always make sure your load does not  exceed the rating of the cord or power strip.

Sorry, I'm not buying.  Show me anything in the NEC that prohibits this.  I've seen a ton of cooked cords and plugs as well, but none that were strictly the result of the practice of simply daisy chaining power strips.  Truthfully, I don't know what state you're in, but I've never heard of this prohibition, and I seriously doubt it's based on science.

I'll say it again.  IMO, there is NO DANGER in simply daisy chaining power strips.  There is CERTAINLY DANGER in overloading multiple power strips, a single power strip, or even a single outlet!  That is a totally different topic, and in no way addresses the topic at hand, please don't muddy the waters, that's a totally different discussion!

I contend if I were to daisy chain three six outlet power strips and plug in fifteen wallwarts with a total power draw for all of them that is far less than the rated power capacity of the outlet in use or the power strips, there would be no more danger than any other wiring arrangement.  If you can show me ANYTHING that factual contradicts my assertion, I'm all ears.  Quite frankly, I'll be very surprised if you can show me anything but an old wives' tale or some lame local regulation that is in no way based on science or safety.

I have some commercial power strips that have a dozen outlets and plug into a single 15A outlet.  Explain to me why that is different electrically than daisy-chaining three power strips to accomplish the same twelve outlets from one 15A outlet.

Don - I agree with all of the above comments about daisy-chaining power strips - it's a bad idea.  I don't know what the typical and total loads are for your lighting transformers and how the lights are distributed on your layout but you might consider a couple of alternatives.  One potentially easy solution is to get one of the long powerstrips that folks use for shop workbenches - they come in various lengths (the one I have is 4 ft) and have single receptacles every 6 inches or so.  that would permit you to plug in the transformers on one strip and you have some flexibility about where you put them.  Another alternative is to power all the lights from a single (or two) dedicated train transformers, which might work if the light voltages fall into the right range for the train transformers.  A plan B part of this option would be to replace all of the incandescent lamps with LED bulbs, which would likely allow you to use just one train transformer.

@richs09 posted:

One potentially easy solution is to get one of the long powerstrips that folks use for shop workbenches - they come in various lengths (the one I have is 4 ft) and have single receptacles every 6 inches or so.  that would permit you to plug in the transformers on one strip and you have some flexibility about where you put them.

Please explain electrically how this is different than using multiple power strips?

John - it isn't, of course, in principle.  As a practical matter, it can be (which doesn't mean that will always be the outcome).  There are a myriad number of things that can go wrong or be over looked - the quality of the powerstrip that you buy for under 10 bucks vs that - like the bench power strip I mentioned - of a more expensive powerstrip.  I think, based on my own experience and observation, that one of the big power strip issues is "mission creep" - you didn't initially plan to have lots of load on the daisy-chained strips, but there it is, with an open receptacle or two and you plug in something else (vacuum cleaner, soldering iron, etc.).  I suspect that from what Don (the OP) said, he probably doesn't have this problem.

A rough analogy (and one where I think we agree) was the discussion about using flammable liquids for track cleaning.  In cases where the there are no nearby ignition sources in the train room (e.g. upstairs room), its not likely to be a problem as long as the quantities aren't large and the room is reasonably well ventilated.  But what about the train room in the basement with the gas-fired furnace and water heater.  Probably not such a great idea (nevermind the issue of toxicity...).  So as a general rule, suggesting the use of flammable liquids for track cleaning doesn't seem very prudent, even though one can make the case 'as long as I use it safely, I'm safe...'.  I think the same reasoning holds for daisy-chaining power strips.

- Rich

It's not just a matter of safety; it's a matter of good wiring practice and logical installation practice.  Why use a bunch of individual wall warts when you can do it much more elegantly with a single power supply? Dept 56 buildings are marketed to folks who arrange them around a Christmas tree, and then box them up for next year.

Just as there is a difference in practice between the track around the tree for a few weeks and the permanent layout, so should there be a difference in thinking about powering permanent accessories on a layout using temporary individual transformers.

Just the simplified wiring should count as a big advantage to using a central power supply.

"Sorry, I'm not buying.  Show me anything in the NEC that prohibits this.  I've seen a ton of cooked cords and plugs as well, but none that were strictly the result of the practice of simply daisy chaining power strips.  Truthfully, I don't know what state you're in, but I've never heard of this prohibition, and I seriously doubt it's based on science."

* * *

The power strips that I have inspected personally were of the very cheap type, and the science, if you insist, is this: The small metal contacts, often not of a large gauge, or of the best quality metal, of an individual receptacle on one strip are not robust enough to handle the combined load of the next strip in line, nor the combined load of the next one added after that one. The entire load of strip #2 and strip #3 is drawn from one of the cheesy receptacles on strip #1, which then overheats and can cause a fire.

Another issue is the arc-flash potential, if and when a load is suddenly and unexpectedly unplugged under power. The resulting arc has been proven (scientifically) to cause fires in drapes, bed clothes, and other combustible materials. The most recent (residential) code requires receptacles that are equipped with arc-fault circuit interrupters (AFCI's) in all rooms except bathrooms.  This applies to all new residential construction and to rooms that are being renovated in existing dwellings. An alternative is to equip the electrical panel with circuit breakers that are AFCI-compliant.

There are so many important things to argue about. Why are we divided over an obvious issue that can be mitigated so easily? This is not an argument about the 2nd Amendment or vax or masks; it's about keeping our group of friends, some of whom often do not understand electricity the way others of us do, safe.

* * *

"I don't know what state you're in..."

New York State Fire Code:

§ F605.5 Extension cords. Extension cords and flexible cords shall not be a substitute for permanent wiring. Extension cords and flexible cords shall not be affixed to structures, extended through walls, ceilings or floors, or under doors or floor coverings, nor shall such cords be subject to environmental damage or physical impact.

* * *

"Show me anything in the NEC that prohibits this."

National Electric Code:

§ 400.7 Uses Permitted.

(A) Uses. Flexible cords and cables shall be used only for the following:

(1) Pendants.

(2) Wiring of luminaires.

(3) Connection of portable luminaires, portable and mobile signs, or appliances.

(4) Elevator cables.

(5) Wiring of cranes and hoists.

(6) Connection of utilization equipment to facilitate frequent interchange.

(7) Prevention of the transmission of noise or vibration.

(8) Appliances where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance and repair, and the appliance is intended or identified for flexible cord connection.

(9) Connection of moving parts.

(10) Where specifically permitted elsewhere in this Code.

* * *

The NEC is not a law, however, an Authority Having Jurisdiction, (the AHJ -- the fancy way of saying your local building inspector, fire marshal or code enforcement official) may enforce the NEC rules if the NEC is added to a local code "by reference." Other than New York City, which is essentially the 51st state when it comes to these administrative laws, I can't think of any AHJ that does incorporate the NEC, by reference, in its codes.

What is all that supposed to mean regarding chaining of power strips? Yes, you can't swap extension cords for Romex.

As John posted, the only real issue with this "practice" is trying to pull too much current through them. That is the basis for any codes or rules or safety practices regarding power strips you guys may enforce. I've dealt with a few building inspectors and they will tell you their job is watch for issues that go against the engineering of whatever is being built, mechanical or electrical. They are not engineers and many times may not understand it themselves.

The OP seems to understand the situation pretty well since he is aware of the current draw of what he is plugging in.

First off, I never said that using multiple power strips in this manner couldn't be misused, anything can be misused.  However, none of the state or NEC quotes had any bearing on multiple daisy-chained power strips.

To be clear, my only objection was the declaration that simply daisy-chaining power strips was more dangerous than plugging them in in parallel.  That is patently false.  The danger is and always has been overloading them.  Obviously, it's also easier to overload them if they're daisy-chained, and I do not now arguing that point, and I never have.  FWIW, I use long industrial power strips for my layout and I don't routinely diasy-chain power strips, but I can't say I never have.  I can say that I've had several power strips that exhibited some sort of contact issue where they had a poor connection to a plug.  When I see that, they hit the trash in a flash!

@Arthur P. Bloom posted:

The power strips that I have inspected personally were of the very cheap type, and the science, if you insist, is this: The small metal contacts, often not of a large gauge, or of the best quality metal, of an individual receptacle on one strip are not robust enough to handle the combined load of the next strip in line, nor the combined load of the next one added after that one. The entire load of strip #2 and strip #3 is drawn from one of the cheesy receptacles on strip #1, which then overheats and can cause a fire.

All of this is simply related to the quality of the power strips, a totally separate discussion.  I'll cheerfully agree with you, I've seen some really cheesy power strips, and I've seen quite a couple that have developed poor contact in an outlet and melted and deformed the plastic case.  I had one at my daughter's place that actually melted enough that it melted the plug firmly in the power strip.  Obviously we corrected that and I supplied here with a few new power strips and removed all the ancient ones she was using.

@Arthur P. Bloom posted:

Another issue is the arc-flash potential, if and when a load is suddenly and unexpectedly unplugged under power. The resulting arc has been proven (scientifically) to cause fires in drapes, bed clothes, and other combustible materials. The most recent (residential) code requires receptacles that are equipped with arc-fault circuit interrupters (AFCI's) in all rooms except bathrooms.  This applies to all new residential construction and to rooms that are being renovated in existing dwellings. An alternative is to equip the electrical panel with circuit breakers that are AFCI-compliant.

Now we're off in the weeds and off the topic. AFCI compliance has nothing directly to do with the power strips.  I believe you'll find that a vast majority of new construction uses the AFCI breakers to meet this requirement.

  For every place in the NEC that it says you can’t do something, I can find an exception that allows it to be done.  The NEC sits the minimum. The NEC is a guide for the LAHJ, because most of those people are not real electricians. In my part of the world most towns don’t have LAHJ’s, so it boils down to my ethics.

  If it was me I’d change the main outlet out to a quad, also very few circuits are only 15 amps, almost everything is 20 amps.

Brad J.

Personally, I would run 12 Gauge Romex from that one 20 amp circuit outlet and replace it with a GFIR, then everything downline is protected, to a 2 gang box with 2 duplex outlets. Obviously if you overload the circuit you're going to blow the breaker and/or GFIR. You want to make sure you're in compliance with state and local fire laws, because if you're not, and you have a fire, your home insurance company might give you the screw job on coverage to fix or replace your home because your wiring was in violation of code by daisying chaining power strips. I was a former School Custodian and Volunteer Firefighter in NYS, we would get written up by OSHA/PESH or Insurance company inspectors for anyone daisy chaining power strips together at the school, or other violations and have to correct the problem ASAP.

The only problem that I see with this is that people forget, things change, and even though you may have carefully thought through how much of a load is present at a given time, there is nothing to prevent the unforeseen. When someone inadvertently plugs that heater into the last open plug on that distant power strip, a meltdown may be the result. Safety first.

What happens in and what is regulated in public and occupational spaces are not applicable to residential dwellings.

On the circuit that feeds all of the wall outlets in my basement are at least 9 receptacles. Other than the solid wire romex, how is this any different than a power strip electrically? Don't assume inferior quality parts.

Let's start with an easier situation. How would you guys handle plugging in extension cords back to back?

This recalls to mind the days of screw in fuses…where the brave put pennies in the fuse socket and put the blown fuse back in until they could install a new fuse

Daisy chaining power strips is like using that penny; it’s proof of a strong religious belief

because like it says on the penny

in God we trust

@1drummer posted:

Daisy chaining power strips is like using that penny; it’s proof of a strong religious belief because like it says on the pennyin God we trust

No comment required.

Yes, I think the drummer has it backwards regarding any religious following here.

@turkey_hollow_rr posted:

What happens in and what is regulated in public and occupational spaces are not applicable to residential dwellings.

On the circuit that feeds all of the wall outlets in my basement are at least 9 receptacles. Other than the solid wire romex, how is this any different than a power strip electrically? Don't assume inferior quality parts.

Let's start with an easier situation. How would you guys handle plugging in extension cords back to back?

And keep that Insurance policy paid up

How exactly do I have it backwards?

@1drummer posted:

This recalls to mind the days of screw in fuses…where the brave put pennies in the fuse socket and put the blown fuse back in until they could install a new fuse

Daisy chaining power strips is like using that penny; it’s proof of a strong religious belief

because like it says on the penny

in God we trust

This is called a strawman argument. You make up something about the misuse of a penny that had nothing to do with this debate and then you try to use that to support your point.

John was correct, this just doesn't deserve comment anymore.

Back to the topic at hand…

Don,

It appears to me you know what you are doing, either way seems fine in my mind. Just don’t go plugging in toasters, microwaves, hairdryers, electric start snowblowers, etc to these strips and you should be okay. Haha!

My only suggestion: if you have not already done so, put LED bulbs in your department 56 buildings. That will help combat the draw on the outlet. I did that for my ~13 ceramic buildings and it greatly reduced my consumption.
I believe Menards buildings are already LED?

Bryce

@Oscale_Trains_Lover_ posted:

Back to the topic at hand…

Don,

It appears to me you know what you are doing, either way seems fine in my mind. Just don’t go plugging in toasters, microwaves, hairdryers, electric start snowblowers, etc to these strips and you should be okay. Haha!

Cool! No mention of a window AC unit so I'm good!

@Don Baird posted:

My layout has a number of Menards’s structures and Dept 56 buildings on it.

I bring the power to a power strip on the control panel. All the transformers are plugged in there. A second power strip is plugged into that and a third into the second. All of these outlets provide power for the Dept 51 & Menards structures.
Is this a problem?

To answer your question plainly, no this is not a problem.

I'm stunned with all the red herring's that were trotted out in order, I suppose, to scare you into another way of thinking.  I would hope it's obvious that you should use decent quality outlet strips in any case, and make sure they're in good condition.  Again, nothing to do with your query, but just addressing some of the other off-the-wall comments in the thread.

Do I recommend this as a general practice?  No.

Have I ever done this?  Yes.

Have I burned my house down, or anybody else's house down?  No.

Top consideration, don't put more load on the whole set of strips than one strip is rated for.  If you're plugging in a bunch of wall-warts that are each consuming 10-12 watts, you'll be hard pressed to overload the outlet strips unless you get up to twenty or thirty of them!

As far as overloads are concerned, you can overload one strip or a bunch of daisy-chained strips, and the same result is likely to be realized, smoke, melting, flame.  That has nothing to do with your query or how you intend to use them.

@turkey_hollow_rr posted:

This is called a strawman argument. You make up something about the misuse of a penny that had nothing to do with this debate and then you try to use that to support your point.

John was correct, this just doesn't deserve comment anymore.

straw man argument creates the illusion of having completely refuted or defeated an opponent's proposition through the covert replacement of it with a different proposition  

I was making a comparison relating to the dangers of using daisy chained power strips.

it’s your false inference that led you down the path you took.

And if it didn’t deserve comment, and yet you commented…

@1drummer posted:

straw man argument creates the illusion of having completely refuted or defeated an opponent's proposition through the covert replacement of it with a different proposition  

I was making a comparison relating to the dangers of using daisy chained power strips.

Other than the obvious issue of overloading the whole string of them, there is no danger in using daisy-chained power strips.  For the OP's use with a bunch of low power wallwarts, this is a non-issue, and he certainly wouldn't be overloading them.  It's no different than using a few cube-taps on a single strip.

By totally changing the subject from power strips to replacing fuses with pennies, you certainly did present a strawman argument.  There is no comparison between the actual topic and putting a penny in a fusebox!

@1drummer, John and I are both electrical engineers, although his circuit experience is light years beyond my own. Even I understand what physically can cause a power strip to fail so we are offering opinions from our understanding of electricity and how it works. Neither of us is suggesting disregarding and residential building codes.

"Never daisy chain power strips."

"You can if you are mindful of the ratings and loads applied."

Which sounds more like trusting your luck, or In God We Trust, as you say?

I have two power strips connected to each other running my entire layout. The first strip has reset on/off switch with a red light. That way I know everything is either on or off. That is the one plugged into my wall socket. I’ve never had a problem with tripping a 15 amp circuit breaker or Legacy/TMCC signals. Here’s what is plugged in.
ZWL transformer powering three lines constantly and three sidings. CW80 powering 34 Z100 switch machines and 10 volt powering signals. Atlas O power pack for turntable power. Two wall warts for Legacy 990 and 993 bases. One wall wart for Legacy Bridge to operate TMCC items. One wall wart for 12 VDC to power LED ‘s and one 180 watt Lionel power supply for turntable tracks. (Only one track is powered at a time). My basement hasn’t blown up yet.

Oh joy.  Another thread featuring two opposing views that, in a race to top each other, are cranking up emotionally more than technically.

This one appears to be Electricians vs. Engineers.  Other recent examples include liberal vs. conservative, and elsewhere on this forum the ever-popular Lionel vs. MTH.

It would be a good thing to try to understand the other side's position before attempting to refute their latest comment.

Construct your comments carefully and think about what they've said, and what you're writing in response at least twice before hitting ENTER.

Having worked on both sides of the wall between electricians and engineers, both are absolutely critical to modern society, and from past experience, each is likely to say to the other "I'm your worst nightmare", and be absolutely correct.

How about calming down?  Starting now?

Mike

Fascinating thread.  I never thought of using a 12 gauge triplex cord for powering three wall warts.

Don, do you have an idea of how many total amps or milliamps of AC you are consuming through the wall warts on your dept 56 buildings?

The reality is simply this.  A typical 120V AC receptacle is rated for 15 amps assuming it has 14 gauge wiring or 20 amps with 12 gauge wiring.  The ground or the third prong is simply a safety device in case your hot side of the receptacle overloads and draws more than the rated amperage for the circuit.

As long as you are not exceeding 15 amps total you will be perfectly safe and meet the code requirements for the rating of a typical residential receptacle.  Even then it assumes that every device is on at the same time to draw the maximum amperage.

It doesn't have to be any more complex than that, engineer - electrician - or other.

I'll speak from a completely foreign perspective, that of a retired semi-pro musician.  Not advocating this at all, but we plugged in an entire rock band setup for a gig during my college days into a mogul screw in adapter from a light bulb. (Mogul as in the type of screw base, not the 2-6-2 )  We did not start a fire and we made a heck of a lot of noise.  I never said we were good, but we sure were loud!

One tool I keep at the house is an infrared digital thermometer for electrical circuits.  With one it is easy to verify nothing is being overloaded or generating heat due to worn or loose connections (the usual culprit verses loading).  Electrical outlets do wear out, especially those in the kitchen or bathroom that get a lot of use.    In my own house and cabin I identified circuit breakers that were getting warmer than they should and several outlets (especially at the cabin) that needed attention.      As for power strips, I now mount the ones I use since the carpet was scorched where a surge protector power strip did it's job,..

Another option, if maybe a costly one if you are concerned, is again to look at the music industry.  I have a Furman power conditioner for my rack mounted music gear that not only limits the amount of draw, but also conditions the power since a 120V AC circuit can vary anywhere from 110V to 130V AC in most cases and sometimes even more variance.  Without getting into the Tesla / Edison argument, AC has the benefit of transmission over long distances, but can be very "dirty" power.  DC has the benefit of great stability but doesn't do as well for transmission over long distances. 

At the same time, a "wall wart" is taking that dirty AC power and converting it to stable low amperage DC power in most cases.  Look at your wall warts, see the amperage or wattage consumption of each and you can do an accurate energy budget for what you are drawing off your electrical systems.

Last thought before I move on to other topics.  If you are in a position to do so, there is nothing wrong with having a licensed electrician add one or more dedicated circuits off your service panel to your train room.  For the limited cost there is a win-win.  You get dedicated power for your trains and you get the peace of mind that you are not going to overload a circuit that has who knows what other devices on it. 

I have a commercial power strip behind my workbench, it has sixteen outlets and terminates in a standard 3 prong plug.  There's no difference between me using that behind there and using three 6-position power strips except this one was much more convenient.

The whole workbench draws maybe 3-4 amps if I turn everything on, but there's a lot of stuff to plug in, DC power supplies, transformers, meters, 'scopes, signal generator, soldering iron, hot air rework tool, bench lights, degausser, etc.