Got a home DIY question - electrical related

**wileyCoyote** · 06-26-2011, 10:30 AM

for the DIY'ers on here,..

i've got a single gang GFCI recepticle in my garage, it's on a 15A circuit. there are some other things on this circuit: a light (switched) in the utility closet, two overhead lights (switched) on the ceiling, an outdoor recepticle on the side of the house.. i think that's it. so i count the "equivalent" of 5 receptacles, counting the GCFI recepticle..

so what i want to do is cutout the box w/ the GFCI recepticle and put in either a two gang or three gang box, so i can have more indoor recepticles (i.e. more than one). BTW, one of the new recepticles i can put in is a combo switch, so i can plug my under-cabinet/task lighting into it.

so, does anyone know if NEC (Edit: sorry not NEMA) specifies a limit on the number of recepticles you can put on a 15A GFCI circuit. if i go to a three gang box, my total "equivalent" number of loads on the circuit would be 7. also, any problem w/ putting the GFCI recepticle in the same box as one or two other recepticles (2-gang, or 3-gang)?

**FORD RECOVERY EXPERT** · 06-26-2011, 10:55 AM

http://www.eng-tips.com/viewthread.c...71770&page=319

This help?

**wileyCoyote** · 06-26-2011, 11:20 AM

yeah, i've read in others online posts/forums about a power (volt-amp) rule to figuring this, ..but then someone on there was saying that didn't apply to residential.. someone else saying that there is no "limit" per se, on the number of receptacles you can have on the circuit.??

15Ax120V = 1800VA (circuit capacity)

90VA per load, 180VA per duplex receptacle.

so for me, currently

GFCI (duplex): 180VA
light in utility room: 90VA
overhead lights : 90VA x 2 = 180VA
outdoor recepticle (duplex) : 180VA

total = 630.

so that means i have some elbow room here? ... so confusing!..

**BrntWS6** · 06-26-2011, 11:39 AM

Some municipalities limit the number of receps on one circuit per there local addendum's (usually 10) but if your not pulling a permit don't worry about it. There is no problem putting a GFCI in with other devices.

If your worried about overloading your circuit just add up total wattage of whatever you have plugged in and your lights and divide by 120v to get amps. Don't exceed 80% of total load. So a 15amp circuit you wouldn't want to go over 12amps.

Just make sure all outlets (not switches or lights) are GFCI protected.

**wileyCoyote** · 06-26-2011, 11:42 AM

Originally Posted by BrntWS6

Some municipalities limit the number of receps on one circuit per there local addendum's (usually 10) but if your not pulling a permit don't worry about it. There is no problem putting a GFCI in with other devices.

If your worried about overloading your circuit just add up total wattage of whatever you have plugged in and your lights and divide by 120v to get amps. Don't exceed 80% of total load. So a 15amp circuit you wouldn't want to go over 12amps.

Just make sure all outlets (not switches or lights) are GFCI protected.

i looked in my municiple code, ...didn't see any big changes, they basically adopt NEC code, there was like one addenda for overhead conductors or something...

i will put the additonal receptacles on the "load" side of the GFCI, so they will be protected.

**BrntWS6** · 06-26-2011, 11:51 AM

Then your fine.....FYI, a dedicated 15amp circuit in a garage is fine for what your doing. Brand new houses get the same treatment.

I've been a licensed electrician for 18years.

**wileyCoyote** · 06-26-2011, 12:09 PM

ok, so my load are:

continuous on:
------------
task lighting (LED): 3 @ 4W/ea. = 12W
overhead lights (CFL): 2 @ 15W/ea. = 30W (CFL bulbs say they are 15W, but equiv output of 65W incandescent)
stereo (a must have!!): = 70W (assuming peak?)

so continuous on total = 112W

intermittent stuff:
------------------
garage vac: assuming 6A motor (peak?), ... = 1200 VA?
light utility room: 65W
bench power strip = ??? depends what you use on it!
mobile garage vac : says "5hp", ..assuming max/peak?

so, basically w/ any utility/power tools, using more than one could easily flip your breaker!

**Silverado2000LS1** · 06-26-2011, 01:04 PM

Originally Posted by wileyCoyote

ok, so my load are:

continuous on:
------------
task lighting (LED): 3 @ 4W/ea. = 12W
overhead lights (CFL): 2 @ 15W/ea. = 30W (CFL bulbs say they are 15W, but equiv output of 65W incandescent)
stereo (a must have!!): = 70W (assuming peak?)

so continuous on total = 112W

intermittent stuff:
------------------
garage vac: assuming 6A motor (peak?), ... = 1200 VA?
light utility room: 65W
bench power strip = ??? depends what you use on it!
mobile garage vac : says "5hp", ..assuming max/peak?

so, basically w/ any utility/power tools, using more than one could easily flip your breaker!

That's right. The inrush current will likely trip your breaker upon startup of the device. However, it may not. At least you will know what caused it if the breaker is tripped. Good Luck.

**BrntWS6** · 06-26-2011, 01:13 PM

Yeah, if your using more that one it will trip but you can avoid that easily.

If that is a central vac it should be on a separate breaker unless someone didn't hook it up correctly.

Inrush current will NOT trip a breaker. If it did i'd be resetting breakers every time I turned on my vacuum. Breakers trip off a dead short or a build up of heat on the line. This takes several minutes to accumulate and open the breaker. Inrush only lasts a second.

**wileyCoyote** · 06-26-2011, 02:02 PM

it's a "garage vac", mounted on the wall... not sure if it is a true central vac or not. (i mounted it on the wall years ago.)

well great - now i find out that the way this was installed the two NM cables coming in the box were epoxied (some kinda glue/epoxy) where the cable meets the box. as if to weatherproof or something. (this is an interior wall)..

WTH? how am i going to get the old box off? how can i remove the expoxy, other than try w/ a knife w/out cutting the sheating?

**Silverado2000LS1** · 06-26-2011, 02:08 PM

Originally Posted by BrntWS6

Yeah, if your using more that one it will trip but you can avoid that easily.

If that is a central vac it should be on a separate breaker unless someone didn't hook it up correctly.

Inrush current will NOT trip a breaker. If it did i'd be resetting breakers every time I turned on my vacuum. Breakers trip off a dead short or a build up of heat on the line. This takes several minutes to accumulate and open the breaker. Inrush only lasts a second.

I agree with you. However, breakers will trip off inrush, depending on the load on the breaker at the time of the unit/appliance being turned on.

**wileyCoyote** · 06-26-2011, 06:18 PM

well i finally got the little ole box off! that sucked! for some reason they (the builder/electrician) put this goop/epoxy-like crap on the cables where they entered the box, i guess as a sealant???? never saw this on any other boxes i've worked on in the house..

anyway, it took me a long time but i was able to free the cables/box from the goop by peeling/chipping away at it w/ a screwdriver - sucks when you're doing this through a small hole in the wall!

so, now, i get my "old work" box in there, and i can't get the cables into the box far enough, ...far enough so that the sheathing is visible inside the box, which code always calls for.. this is because the design of the box and lenght of the tabs is different on the new box.. so, i guess the only thing i can do is enlarge my hole in the wall and move my new box up an inch, probably two inches, so i can get the cables in far enough to show sheathing? ... ahhhh, damn DIY projects!

**Zapper2003** · 06-26-2011, 07:04 PM

1. Ignore code.
2. Install new box.
3. ?????
4. Profit

**wileyCoyote** · 06-26-2011, 07:06 PM

what's 3. ?

**Zapper2003** · 06-26-2011, 07:07 PM

just use electrical tape. to hell with wirenuts and whatnot. it will be fine.

**wileyCoyote** · 06-26-2011, 07:11 PM

i thought you were going to say 3=drink beer..

i got wire nuts and electrical tape - i'm gonna use everything i got!

besides,..i gotta have some peace of mind my house won't catch on fire!

**BrntWS6** · 06-27-2011, 07:36 AM

Originally Posted by Silverado2000LS1

I agree with you. However, breakers will trip off inrush, depending on the load on the breaker at the time of the unit/appliance being turned on.

Is it possible....yes. But as a rule of thumb inrush won't trip a breaker, especially in residential. The rating on a typical mag breaker is 10x the handle rating.

**ssgtcarroll** · 06-28-2011, 04:40 AM

Should fix it all together. Garage should be 20 amp. Light circuts shouldn't be on receptical circuts (turn something on lights flicker).

Does your garage have a seperate panel?

**wileyCoyote** · 06-28-2011, 06:35 AM

i have a separate 20A circuit, but it's dedicated to the garage door opener.

can't say i've ever seen light flicker.., but i have CFL bulbs in my two overhead lights, and i just put in low-energy LED task under-cabinet-style lights.

**wileyCoyote** · 07-04-2011, 10:33 AM

well, i think i finished up. ... once again i learned that things are not as easy as they may seem when it comes to home projects! relocated the outlet box 2" higher, and used a new 3-gang box, installed a duplex GFCI, a duplex receptacle, and a combo switch/receptacle (i plug my under cabinet task lighting into).. so far, so good i think, nothing blew up yet!

thanks for everyone's help!