On Wed, 11 Jun 2008 17:53:17 +0000 (UTC) ranck@[EMAIL PROTECTED]
wrote:
| Yesterday I got a call from someone asking about how to
| wire up some sockets and lights in a basment remodel.
| The specific question was about the breaker size since
| the box the outlet came in specified a 15A breaker.
| I asked what guage wire he was running and since it was
| 14ga told him to use 15A breakers.
|
| Now the question. Has the code changed in recent years
| to disallow 15A (NEMA 5-15) outlets on 20A circuits, assuming
| of course the circuit uses 12ga wire? I know there used
| to be specific exemption for 15A rated outlets on 20A wiring.
| Have they taken that away, or was warning on the box some
| legal CYA? Just curious.
It could be CYA. Or it just could be a simple error by the writer
of those instructions.
The code has not changed with respect to the outlets. You can use
15A style outlets on a circuit protected with a 20A breaker so long
as there is at least 2 such outlets on that circuit. The biggest
question is the size of wire. If it is #14 CU then it needs to be
protected at the 15A level and then no 20A style outlets are allowed.
If the wire is #14 CU then the breaker must be 15A and the outlet or
outlets must be 15A.
If the wire is #12 CU and there is only one outlet, 15A or 20A, the
breaker and outlet must be the same rating.
If the wire is #12 CU and there are multiple outlets, a 15A breaker
may be used but only with 15A outlets (no 20A outlets).
If the wire is #12 CU and there are multiple outlets, a 20A breaker
may be used with any mix of 15A and 20A outlets (including only 15A
outlets).
I don't really see a reason having a 20A breaker on a #12 CU circuit
with a single 15A outlet is a safety hazard (since the appliance would
not use more than 15A and if it did, the wiring is rated for 20A and
the breaker woukd trip above that). But the code currently does not
allow that.
Apparently, all 15A outlets are capable of handling 20A, at least in
the common part. The 20A plug has the same contact surface area as
a 15A plug, so I don't see that this is the issue. If UL tests all
outlet devices that are of the NEMA 5-15R configuration as if they
were of the 5-20R configuration, and they pass, it should be safe.
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