# Device Box Size For GFCI



## icepal1999 (Jul 23, 2008)

Hey All,

Is there a minimum device box size for GFCI's? I have an old house and the device box is damn small - so small I almost have to smash with my hand to get the GFCI to fix in the box. I want to replace the box with a larger size so the GFCi fits nice and the conductors are not crushed/smashed as well.

Thanking you in advance.....


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## chris75 (Aug 25, 2007)

icepal1999 said:


> Hey All,
> 
> Is there a minimum device box size for GFCI's? I have an old house and the device box is damn small - so small I almost have to smash with my hand to get the GFCI to fix in the box. I want to replace the box with a larger size so the GFCi fits nice and the conductors are not crushed/smashed as well.
> 
> Thanking you in advance.....


 
No, but if the box is way to small use a gfci breaker. Or replace the box with more cubic space.


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## icepal1999 (Jul 23, 2008)

Yeah I want to replace the box - is there a min size - say 18cu or 21cu?


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## Yoyizit (Jul 11, 2008)

My local Code people said a GFI does not require a larger box, but I had the same problem as you. 

Logically, a bulky GFI seems to violate single gang box fill requirements if box fill is based on 
free air circulation within the box and 
current through the wires in the box and 
not wanting to damage conductor insulation.

Before you buy the Old Work box, check if you have 3-1/2" depth or 2-1/2" depth between drywall surfaces. Some interior partitions use 2x3s.


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## jbfan (Jul 1, 2004)

icepal1999 said:


> Yeah I want to replace the box - is there a min size - say 18cu or 21cu?


How many wires in the box?
2 sets of wire, use the 18 cu, 3 sets of wire use the 21 cu box.
There is not a min, but you do not want to crush the wires.


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