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Old 03-18-2010, 09:02 PM   #1
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Any limit on number of outlets per breaker?


Within the same area (in this case a 14x20 attached garage) would it be permissible to run 6-8 outlets and one light off a single 20 amp breaker? Assume the high number of outlets is for convenience such as being to plug in a shop vac where needed and does not reflect intent to use several at the same time.

Wondering too if a single GFI circuit in small garage is adequate or is there something mandating 2 such circuits?

Thanks for the help.


Last edited by Mi Feller; 03-18-2010 at 09:13 PM. Reason: mis-fire
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Old 03-18-2010, 09:40 PM   #2
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Any limit on number of outlets per breaker?


Single circuit GFCI protected is all that is needed
No limit on the number of outlets

I'd run (2) 20a circuits myself
And I'd put the lights on a lighting circuit

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Old 03-18-2010, 10:00 PM   #3
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Any limit on number of outlets per breaker?


Will run 2 circuits. One with the GFI outlets and another with lights and probably ceiling outlet for opener which doesn't need to be GFI if out of reach from floor level. Have larger detached garage which gets heavy use. This one just really for parking car. Thank you and good evening.
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Old 03-18-2010, 10:08 PM   #4
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Any limit on number of outlets per breaker?


Actually NEC 2008 did away with the exclusion for the door openers
Under NEC 2008 all outlets in the garage need to be GFCI protected
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Old 03-19-2010, 06:45 AM   #5
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Any limit on number of outlets per breaker?


You can run a MWBC (multiwire branch circuit) for your outlets, then a separate lighting circuit. This would give you two separate outlet circuits and save money.

You run a 12/3 cable from the panel. White goes to the neutral bar, black and red each go to their own breaker. The breakers have to be next to each other (vertically) and be on different hot busses. They also have to be tied together with handle ties (or use a double-pole breaker) so they go on and off together.

Then run 12/2 or 14/2 for your lighting.
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Old 03-19-2010, 07:56 AM   #6
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Any limit on number of outlets per breaker?


Quote:
Originally Posted by secutanudu View Post
You can run a MWBC (multiwire branch circuit) for your outlets, then a separate lighting circuit. This would give you two separate outlet circuits and save money.

You run a 12/3 cable from the panel. White goes to the neutral bar, black and red each go to their own breaker. The breakers have to be next to each other (vertically) and be on different hot busses. They also have to be tied together with handle ties (or use a double-pole breaker) so they go on and off together.

Then run 12/2 or 14/2 for your lighting.
Secutanudu...you should also mention that on a MWBC the neutral has to be "pig-tailled" at the points where devices are attached, ie. receptacles, lamp holders, so as not to break the continuity of the neutral if the device were to be removed. See 300.13 (B) Device Removal.
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Old 03-19-2010, 08:07 AM   #7
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Any limit on number of outlets per breaker?


Thanks, Kyle. Didn't know that. Why does the fact that it's a MWBC make it more dangerous to disconnect a neutral than a normal circuit?

Here's that section of the code you mentioned, showing that you are correct:
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Old 03-19-2010, 08:50 AM   #8
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Any limit on number of outlets per breaker?


I'm on dial-up, so it's not easy for me to jump around the internet and find a picture to be able to post here. I'll try, but someone else may beat me to it...which is fine with me.

If you were to lose the connection of the neutral, especially at the point of origin (the panel), the circuit instantly becomes a 240v circuit. Electricity is trying to find it's way back to the source, and will use any means possible. Example....Imagine no neutral connection at the panel...power leaves the black wire...goes through a TV (or whatever), returns to the receptacle, leaves the receptacle on the WHITE wire, goes to the next receptacle and enters on the WHITE, goes through a hair dryer (example) and leaves on the RED wire and goes back to the panel. With a properly installed circuit, the Black and Red wire would be on different busbars....hence 240V potential between black and red.
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Old 03-19-2010, 09:18 AM   #9
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Any limit on number of outlets per breaker?


Got it, thanks. I guess it'd drop down voltage due to the resistance in your loads...maybe to 180v or something?
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Old 03-19-2010, 09:42 AM   #10
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Any limit on number of outlets per breaker?


Correct, depending on the resistance of the loads, which are now in series. And your example of dropping down to 180v most likely would fry that particular device.

Can't yet find the picture I'm looking for, but maybe these will help.
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Old 03-19-2010, 09:49 AM   #11
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Any limit on number of outlets per breaker?


Another thought...if one or both circuits in a a MWBC neeeds GFCI outlets (like the OP will need in the garage), would this require GFCI outlets at every location, since the outlets would have to be pigtailed? Put more simply, does 300.13 (B) prevent wiring downstream devices from the LOAD side of a GFCI outlet?

Maybe the best way to GFCI protect a MWBC is with GFCI breakers?
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Old 03-19-2010, 10:00 AM   #12
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Any limit on number of outlets per breaker?


GFCI receptacles work fine on MWBC's if they are installed correctly. You must fully understand both MWBC's as well as GFCI's. IMO untrained people should not even try to use MWBC's.

Last edited by brric; 03-19-2010 at 10:03 AM.
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Old 03-19-2010, 10:29 AM   #13
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Any limit on number of outlets per breaker?


How are GFCI's properly installed on MWBC? As long as it is installed with pigtails, can you feed downstream outlets off the load side?
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Old 03-19-2010, 11:17 AM   #14
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Any limit on number of outlets per breaker?


See Stubies diagrams for GFI's on MWBC's.



Last edited by brric; 03-19-2010 at 11:20 AM.
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