Electrical question for the code people

[Rob Russell]

[Another observation - the ground prong is always up, whereas in most residences around here the ground prong is down. But I'm not asking about that.]

There are places where the electricians flip switched duplex receptacles th be the opposite from non-switched receptacles. That, in theory, makes it easier for a homeowner to tell which receptacles are the swithced ones to plus a light into vs. the unswitched ones for the vacuum cleaner.

Rick's right that there is nothing in the NEC that requires installation with ground pin up or down. In fact, if you want to see a "Festool vs EurekaZone" or "Sawstop good or bad" like flamefest, check out some of the threads on Mike Holt where the pro sparkies go at it on the "correct" or "best" orientation for a duplex receptacle. You'd have to do some historical searches - that topics's been beat enough so the mods there pretty much don't tolerate any new rows that start on that topic.

[Mike Henderson]

Thanks for the information, everyone. I also sent an e-mail to a friend of mine who designs commercial electrical installations for the company he works for. He's an interesting guy to talk with because he works on some big projects.

Anyway, here's what he told me - if I understood it correctly.

In general, the breaker and the outlet are matched, i.e., 20 amp breaker, 20 amp outlet(s). An exception was carved out for residential and light commercial which allows 15 amp multi-drop outlets on a 20 amp circuit. But if there's only one outlet, the two match.

For hospitals (around here), he commented that they usually only allow four 20 amp outlets on a 20 amp circuit to minimize nuisance tripping.

In general, I think this is the same as what you've all been saying.

Again, thank you for helping me satisfy my curiosity.

Mike

[Chris Padilla]

Since there are receptacles that accept BOTH configurations of plugs in 15 and 20 A applications, why not just install those on the 20 A branch? I guess in a pinch, it can still be acceptable to install a 15 A only receptacle on a 20 A branch...good to know.

[Mike Henderson]

Since there are receptacles that accept BOTH configurations of plugs in 15 and 20 A applications, why not just install those on the 20 A branch? I guess in a pinch, it can still be acceptable to install a 15 A only receptacle on a 20 A branch...good to know.

Where I shop, the 15 amp outlets are cheap, but the 20 amp outlets (actually dual 15/20) are not - they're quite a bit more expensive. I think it's because there's a big volume of 15 amp outlets sold.

Mike

[Thomas Syrotchen]

Interesting, I guess we assume that in order to pull 20A the device must have the different prong configuration and therefore any device plugged into a 15A outlet will only be capable of pulling 15A. I can just hear it now, darn honey these jokers that built my new planer put the wrong plug on the end of it. I know its 110V I told that guy I only had 110V in the shop and it says 110V on the motor. Guess I'll have to go to the hardware store and get me the right kind of plug. A quick lesson on how to make your white plugs black without paint. Sorry about the sarcasm but doesn't that seem strange, I understand the price difference in the 15A v. 20A plug but in the big scheme of things the copper wire will cost more than the plugs not to mention if more 20A receptacles were installed the cost would likely go down. I guess its just engrained in my brain, circuit protection should protect the circuit.

Thanks for the info, obviously I never realized that was legal in residential.

[Chris Friesen]

Where I shop, the 15 amp outlets are cheap, but the 20 amp outlets (actually dual 15/20) are not - they're quite a bit more expensive. I think it's because there's a big volume of 15 amp outlets sold.

Are you comparing apples to apples? Pretty much all 20A outlets are "spec grade", while most of the 15A outlets are just basic crap homeowner grade. "spec grade" 15A outlets are a lot more expensive.

[Mike Henderson]

Are you comparing apples to apples? Pretty much all 20A outlets are "spec grade", while most of the 15A outlets are just basic crap homeowner grade. "spec grade" 15A outlets are a lot more expensive.

That's probably true. I used the low cost ones in my shop and haven't had any problems with them. I bought several of the "contractor pack" of 15 amp outlets.

My guess is that they don't make the low cost versions of the 20 amp outlets.

Mike