15A recepticals on 20A circuit


Old 07-23-11, 12:49 AM
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15A recepticals on 20A circuit

While adding a receptacle to our living room circuit, I realized all the receptacle circuits in our 50 year old S. Calif tract house have 15A receptacles, but they are protected by 20A breakers. The cable to and beyond the 15A receptacle I exposed was 12-2... good for 20A. I bought a 20A preferred grade receptacle to compare to the 15A one. The little breakout tabs between the two screws (that I can use to turn the duplex receptacle into two separately wired receptacles) on the 20A one appears slightly larger than on the 15A one. Is this the limiting component of the 15A receptacles, as all downstream current drawn must past thru these tabs (as the feeding cable uses one pair of screws and the beyond cable uses the other pair). Can 20A pass thru a 15A rated receptacle? Or do I need to replace all my 15A receptacles with 20A receptacles, or rewire all 15A receptacles using pigtails (in-order for heavy down-circuit load to bypass those tabs)? Might have this been OK 50 years ago, but not to code now? Could the former owner replaced all the 15A BR & LR receptacle circuits with 20A breakers? (The light circuits are 15A.) FYI, my master bath receptacle is at the end of a circuit serving two bedroom receptacles. I read on this site that bathrooms now require their own circuit. Year's ago I replaced the first receptacle in this circuit with a 15A GFI receptacle. We've had no problems with this circuit.
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Old 07-23-11, 01:55 AM
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Nothing wrong with this as far as NEC is concerned (CEC requires 20A T-slot receptacles on 20A circuits), and it is very common. 15A receptacles are rated for 20A passthrough. The only thing limiting you to 15A is simply the orientation of the slots. 99.9% of household devices have 15A 'straight slot' plugs, so receptacles that can accommodate 20A plugs are unnecessary in the house.. You'd even be hard pressed to find a shop tool with a 20A plug.

Pigtailing so the passthrough is not dependent on the device is good practice, but not required. Using the screw terminals or backwire (screw clamp) connections for passthrough is ok, but IMO requires more work than just pigtailing it, so to do it is a waste of time. Passthrough utilizing backstab (push-in) connections, while not prohibited is considered extremely bad practice (it's very amateur, and if you ever catch an electrician doing this you should question his credentials).

As long as the wire is #12, it is perfectly ok to have a 20A breaker protecting it. I forget off the top of my head which code cycle it started with but bathrooms require their own 20A circuit for the receptacles only. Lighting circuits can still be shared. It's probably overkill to have the GFCI protecting the entire existing circuit unless they are kid's rooms, so you could safely move the GFCI device into the bathroom if you want.
Old 07-27-11, 10:01 PM
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JerseyMatt -- tx for the answer -- so I'm OK to leave the original wiring as is. Maybe when I'm retired and painting the house interior, I'll go thru and convert them to pigtails. And thanks for elaborating -- the warning about not to passthru the backstab connections... I'll have to question the guy's credentials who rerouted a few cables running along my attic floor (so I could lay flooring) by splicing a pair of receptacle boxes into each circuit with enough new cable to span the gap between boxes along the relocated path. He used the backstab connections in a pass thru manner. I was concerned about it but let him do it. Won't have trouble finding this amateur... he's yours truly. I'll go fix them soon.
And yes, the GFCI was put in my young son's bedroom.
Old 07-28-11, 08:33 AM
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Backstabs are legal, so it's technically not wrong to do it that way, but the connections probably will not last as long. They're basically the least-labor option for contractors trying to work fast.
Old 07-28-11, 09:00 AM
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Bob - Are you sure your electrician used backstab connections and not backwired? Both designs use similar techniques, strip a wire and stick it in a hole, but the backwired uses a screw tightened internal clamp while the backstab uses an internal spring clamp to grip the wire.
Old 07-28-11, 09:33 AM
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Wayne....have to read that last post of Bobs more closely...

"Won't have trouble finding this amateur... he's yours truly."

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