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Electrical outlet standards

Electrical outlet standards

Electrical outlet standards

Is there a standard on dimensions of a duplex receptacle on a single yoke? We are looking to manufacture an additional circuit to be added to the back of a standard 5-15 outlet which would give us wireless control over it. According to the NEC and NEMA the receptacle counts as 2 conductors multiplied by the volumetric allowance for the largest wire in the box. I need to know how much volume the receptacle can take up to maintain compliance. For example in a 18in3 electrical box with 2 14/3 wires how large an area may the receptacle (mounted on a single yoke) use. Is this regulated?

Thanks in advance,


RE: Electrical outlet standards

Link to Nema dimensions:


David Baird

Sr Controls Designer
EET degree.
Journeyman Electrician.

RE: Electrical outlet standards

Thanks for that, I've actually read that standard and it regulates the face dimensions but not the depth. A NEMA representative suggested using GFCIs, etc as a guideline but as far as percentage of box thast can be filled or back clearance, it seems is not regulated.

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