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Power for New Layout Room

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  • Member since
    May, 2004
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Posted by 7j43k on Friday, May 25, 2018 10:45 AM

oldschoolmarine

PS:....... It's "...heed this advice..." 

 

Hey Teach

Can we take the weekend off

we all at one time or another live it that "Glass House"

 
 
 

 Perhaps if you had been maligned concerning your professional ability and competence, you would have been a bit huffy, too?

 

You do recall you have to do your assignments over the weekend!  I want to see THREE weathered freight cars on my desk when we come back to school.  And be SURE to copy little Eric over there.

 

 

Ed

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  • From: Maryland
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Posted by ATLANTIC CENTRAL on Friday, May 25, 2018 3:46 PM

7j43k

 

 
ATLANTIC CENTRAL

The restriction is the square footage of the building that a single circuit can serve, and/or the requirement of specific circiuts for special/dedicated loads.

A 15 amp general receptacle circuit may serve 600 sq ft, 20 amp circuits may serve 750 sq ft. The number of devices is determined by other factors, wall arrangments, required spacing, etc.

Sheldon

 

 

 

I am not aware of that 600/750 sq ft "rule".  Where would I find it?

I know of the 3 watts per square foot general lighting load for dwellings.  I believe you would then divide that total number by either 2400 or 1800 (20A or 15A) to get the required number of general lighting circuits.

I believe you may apportion the required outlets any way you want on the resulting circuits.  But I would recommend making them "evenly balanced", so as not to upset the inspector.  Or the homeowner, for that matter.

 

 

Ed

 

From the 2002 NEC (because it is what I had handy, and I'm pretty sure it has not changed)

NEC - article 220.3(B) - paragraph (10) Dwelling Occupancies. In one-family and two-family, and multifamily dwellings and in guest rooms of hotels and motels, the outlets specified in (1), (2) and (3) are included in the general lighting load calculations of 220.3(A). No addtional load calculations shall be required for such outlets.

The 3 volt-amperes per square foot you are refering to comes directly from the NEC Table 220.3(A) refered to above.

So, separate from additional special loads and requirements (kitchens, baths, fixed hard wired equipment, etc), the general lighting and receptacle requirement for dwellings is 3 VA per square foot.

600 sq ft x 3 VA = 1800 VA / 120 = 15 amps.

750 sq ft x 3 VA = 2250 VA / 120 = 18.75 amps

Other related sections make it clear that these circuits do not need to be de-rated for these calculations.

Sheldon

    

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Posted by 7j43k on Friday, May 25, 2018 4:18 PM

Sheldon,

 

I see.  Pretty much saying the same thing, differently.  I thought you might be saying it was an explicit statement in the code, which it doesn't seem to be.

 

Ed

  • Member since
    January, 2009
  • From: Maryland
  • 7,279 posts
Posted by ATLANTIC CENTRAL on Friday, May 25, 2018 4:34 PM

7j43k

Sheldon,

 

I see.  Pretty much saying the same thing, differently.  I thought you might be saying it was an explicit statement in the code, which it doesn't seem to be.

 

Ed

 

No, it does not spell out the 600/750 sq ft numbers, but the code is pretty specific about the method of calculation.

Remember, that is the minimum requirement, you are welcome by code to have more circuits.

My 1901 Queen Anne is rewired to nearly commercial standards. Nearly all circuits are 20 amp (which contrary to some armchair experts, is completely legal), and in the case of bedrooms, typically 250 sq ft each, a single 20 amp circuit only serves two rooms.

So that is 4.8 VA per square foot.

I stapled every foot of wire, and turned every wire nut..........

Sheldon

    

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Posted by 7j43k on Friday, May 25, 2018 5:44 PM

Sounds good.

Yeah, SOME electricians go totally nuts on their own places.

Mine:  1914 Brown Shingle--74 breakers.  

 

Ed

  • Member since
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  • From: Maryland
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Posted by ATLANTIC CENTRAL on Friday, May 25, 2018 6:21 PM

7j43k

Sounds good.

Yeah, SOME electricians go totally nuts on their own places.

Mine:  1914 Brown Shingle--74 breakers.  

 

Ed

 

Sounds cool. I love all that pre 50's architecture.......

74 breakers, that sounds like this place, but you might have me beat by 5 or so. 40 ckt QO 200 amp main panel and three subs, one sub in the house and two in the garage. One of the two in the garage is just for the train room which is the second floor.......

That is why I used mostly 20 amp circuits, I knew it would fill up fast.......

Sheldon

    

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Posted by 7j43k on Friday, May 25, 2018 7:01 PM

Very excellent.  QO's are neat.  I put in GE's, which I rather like.

 

Ed

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Posted by Atchee on Saturday, May 26, 2018 6:50 PM

As a master electrician with 45+ years in the trade I get real nervous when people not specifically trained in the trade start offering any advice on residential or commercial wiring. ESPECIALLY in a forum not dedicated to the topic.

I understand budget constraints, and have nothing against DIY work.  BUT if you are doing the work unpermitted and don't know if your local jurisdiction has  ammendments to the NEC, do yourself a favor and either ask an acquaintance that does know or pay somebody that does to look your stuff over.

As an aside, a lot of places keep pretty detailed records about what has been permitted on a property.  Nothing like getting ready to sell the place and have the home inspector check on improvements that were done, then the bank refusing to finance the buyer because there's no record of, say, a finished basement being permitted and inspected.

Then you may wind up removing a bunch of drywall so framing, insulation, electrical, etc., etc. can be checked.  After paying double for a permit and possible fines to boot.  You wouldn't believe what I've seen a building department force someone to tear out.

Just sayin'

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Posted by jjdamnit on Saturday, May 26, 2018 7:01 PM

Hello all,

MGAMike
MGAMike
So I sat down with my licensed contractor...

Glad to hear that!!!

Well done!

The proper authorities have been notified and a solution found.

Hope this helps.

 

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

  • Member since
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  • From: Maryland
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Posted by ATLANTIC CENTRAL on Saturday, May 26, 2018 8:37 PM

Atchee

As a master electrician with 45+ years in the trade I get real nervous when people not specifically trained in the trade start offering any advice on residential or commercial wiring. ESPECIALLY in a forum not dedicated to the topic.

I understand budget constraints, and have nothing against DIY work.  BUT if you are doing the work unpermitted and don't know if your local jurisdiction has  ammendments to the NEC, do yourself a favor and either ask an acquaintance that does know or pay somebody that does to look your stuff over.

As an aside, a lot of places keep pretty detailed records about what has been permitted on a property.  Nothing like getting ready to sell the place and have the home inspector check on improvements that were done, then the bank refusing to finance the buyer because there's no record of, say, a finished basement being permitted and inspected.

Then you may wind up removing a bunch of drywall so framing, insulation, electrical, etc., etc. can be checked.  After paying double for a permit and possible fines to boot.  You wouldn't believe what I've seen a building department force someone to tear out.

Just sayin'

 

Having been an electrician and a home inspector at various points in my life, I'm happy that even here in the Peoples Republic of Maryland we have not gotten to that level of intrusive government yet.

I agree that people who lack the proper knowledge or skills should not be doing electrical work (or plumbing, or HVAC, or even carpentry for that matter), but just because someone is not working in a trade does not mean they lack the knowledge or skills.

Several counties here in Maryland have homeowner programs that allow homeowners to get their own permit and do their own plumbing and electric after a simplified test.

Your comment about unprofessional advice is why Ed and I spoke up earlier, too much mis-information.

Sheldon  

    

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Posted by SeeYou190 on Wednesday, May 30, 2018 4:46 PM

OK, I am going to jump into this one, even though I am more than a year from beginning construction of the layout room.

.

My electrician (I have an awesome electrician, his work on the kitchen and entertainment center have been A+) decided that a 20Amp dedicated circuit for the train layout will be sufficient.

.

The layout is going into an existing area, so it is already wired for wall outlets, overhead lighting, etc. The 20 amps additional it only for the layout.

.

The wall switch will be keyed, and the outlet where the layout plugs into the wall will be a twist lock type. All the layout legs will be Edsal steel legs as shown.

.

.

All the power for lighting and the workbench will come from the existing circuits already in the room. My single story Florida house does not have a basement or attic.

.

The layout legs will all have convenience outlets built into them The Edsal legs are already punched out for duplex outlets in metal electrical boxes.

.

This allows me to unplug the layout when I am away eliminating any possible problems or worries while I travel. The key prevents unauthorized train operation if the (yet to be created) grandkids come over. The convenience outlets in the steel legs will be very helpful.

.

Does all this sound correct? Is this a bad plan? Am I missing something?

.

-Kevin

.

Happily modeling the STRATTON & GILLETTE RAILROAD located in a world of plausible nonsense set in August, 1954.

  • Member since
    January, 2009
  • From: Maryland
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Posted by ATLANTIC CENTRAL on Wednesday, May 30, 2018 8:35 PM

SeeYou190

OK, I am going to jump into this one, even though I am more than a year from beginning construction of the layout room.

.

My electrician (I have an awesome electrician, his work on the kitchen and entertainment center have been A+) decided that a 20Amp dedicated circuit for the train layout will be sufficient.

.

The layout is going into an existing area, so it is already wired for wall outlets, overhead lighting, etc. The 20 amps additional it only for the layout.

.

The wall switch will be keyed, and the outlet where the layout plugs into the wall will be a twist lock type. All the layout legs will be Edsal steel legs as shown.

.

.

All the power for lighting and the workbench will come from the existing circuits already in the room. My single story Florida house does not have a basement or attic.

.

The layout legs will all have convenience outlets built into them The Edsal legs are already punched out for duplex outlets in metal electrical boxes.

.

This allows me to unplug the layout when I am away eliminating any possible problems or worries while I travel. The key prevents unauthorized train operation if the (yet to be created) grandkids come over. The convenience outlets in the steel legs will be very helpful.

.

Does all this sound correct? Is this a bad plan? Am I missing something?

.

-Kevin

.

 

Well Kevin, your electrician is right, a 20 amp circuit is plenty for any "room sized" layout, even a "big room".

I think the key switch and the twist locks are over kill, but I would switch the circuit so you can kill everything on the layout with one switch.

Again, not sure I would use the metal legs, but I don't see a problem with that or the outlets mounted in them.

Sheldon 

    

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    February, 2002
  • 180 posts
Posted by andychandler on Thursday, May 31, 2018 7:47 PM

my basement room is 11x13 so I wiredit myself using an existing but unused 20 amp circuit and added another.  I use seperate circuits for lighting and wall plugs/layout power.  And yes use modern lighting, LED's, which draw lower amperage and produce less heat.  I was finding the incandescents were generating too much heat in summer (I live in Georgia).  Also did my research and read the code for my area.  I found it not as hard as two rail wiring!  best regards, andy chandler

Andrew D. Chandler
  • Member since
    January, 2017
  • From: Southern Florida Gulf Coast
  • 2,737 posts
Posted by SeeYou190 on Thursday, May 31, 2018 9:29 PM

ATLANTIC CENTRAL
Well Kevin, your electrician is right, a 20 amp circuit is plenty for any "room sized" layout, even a "big room".

.

To be fair, he said 15 amps would be enough, but for the type of hardware I wanted, and the key locking switch he said that the price difference would be less than $25.00 to make it 20 amp... so might as well do that. He said the jump to 30 amps would be much more expensive... and completely unnecessary.

.

-Kevin

.

Happily modeling the STRATTON & GILLETTE RAILROAD located in a world of plausible nonsense set in August, 1954.

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