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J. Clarke J. Clarke is offline
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Default Shop Wall and Electric

On 8/31/2010 1:25 AM, Josepi wrote:
15 ampere recepticals, or any 15A device, requires a 15A breaker to protect
it in our code.


It would help if you stated what specific code you are referencing.

NEC allows 15A receptacles on 20A circuits as long as there are multiple
receptacles. See Table 210.23(B)(3).

If you are constrained by a local code which is not based on NEC then YMMV.

Why not run 14Ga wire on a 20A breaker then?


Because code does not allow it.

Now you plug in a #18 Ga lamp socket and cord wire into a 20A circuit?


Code ends at the receptacle. Whatever is plugged into that receptacle
may be subject to fire codes, construction codes, or other safety codes,
but it is not in general addressed by the National Electrical Code.

The
15A circuit was bad enough that they have to tell you not to conceal a lamp
or extension cord so the heat can escape...LOL


The breaker is not there to protect portable appliances.

"Scott wrote in message
.. .
You are mistaken. The code requires a certain density of
receptacles in a bedroom. The ampacity of the branch circuit is
calculated based on the number of receptacles on a branch circuit and some
very conservatively (err on the side of safety) estimated expected loads.

The gauge of the branch circuit wiring is based on the rating of the
overcurrent
protection device with the required branch circuit ampacity. An
overcurrent protection device rated at 20 amperes, will require a mininum
of AWG 12 wire (possibly AWG 10 depending on the distance between the
overcurrent protection device and the set of protected devices to avoid
excessive
voltage drop).

The typical residential duplex NEMA 5-15R receptacle is rated to support two
devices
which combined, must not consume more than 1.8KW. These receptacles
will accomodate only NEMA 5-15P plugs. NEMA 5-20R duplex receptacles
are available that will accomodate both 5-15P and 5-12P plug, but are very
uncommon in residential work.

Note again, the branch circuit wiring is always sized to the overcurrent
protection device, not the branch device, so a 20A breaker protecting four
or five NEMA-15R duplex receptacles would require miniumum AWG12 wiring
throughout the branch circuit.

scott