220 Volt Plugs

[Stormin Mormon]

This way, they could use the range and the AC at the same time.

[trader4]

I think one key point here is that the "device", ie appliance is listed with the cord and plug it came with. Can you change that cord to a heavier gauage, I think so. Can you change the 15 amp plug it came with to a 30 amp? What gfre provided would seem to suggest the answer is no:

(1) Supply Cord of Listed Appliance or Luminaire. Where flexible cord or tinsel cord is approved for and used with a specific listed appliance or luminaire, it shall be considered to be protected when applied within the appliance or luminaire listing requirements. For the purposes of this section, a luminaire may be either portable or permanent.

[krw]

Oh, good grief. How many times must you be told that "code" has nothing to say about appliances. Learn to read.

[krw]

No, he's just as pig-headed about using Google as you were about top-posting.

[krw]

Copper and aluminum isn't a problem as long as listed CU-AL connections are used between. Aluminum caused all sorts of grief but it was eventually sorted out. Some of the problems were labor quality (AL is less forgiving) and others were metallurgy. AL us still widely used for large appliances (clothes dryers and ranges) with very few issues.

[trader4]

You should be the last one to talk about anyone being "pig-headed". Google, not being client based, offers me the option of using it anywhere. But I'm sure that's beyond your pay grade.

[Tony Hwang]

Hmmm, My previous house built in the mid-70s during Cu hortage had all Al wiring, never had any trouble and still the house is there(did not burn down, LOL!) What?! is there any one whose knowledge is based on Google? How did (s)he lived B4 the days of I'net? IMO, intelligence does not come from Google.

[gfretwell]

Yup

210.19(A)(3)ex1

Exception No. 1: Conductors tapped from a 50-ampere branch circuit supplying electric ranges, wall-mounted electric ovens, and counter-mounted electric cooking units shall have an ampacity of not less than 20 amperes and shall be sufficient for the load to be served. These tap conductors include any conductors that are a part of the leads supplied with the appliance that are smaller than the branch-circuit conductors. The taps shall not be longer than necessary for servicing the appliance.

[clare]

Except tou cannot legally (or practically) connect a 15 amp receptacle to an 8 guage wire.

[clare]

Been in my 40 year old house 32 years now - all aluminum wiring - and never a connection problem. Had a couple non-co/alr outlets overheat - but not at the wiring connection. Just cheap-ass low-buck outlets that got a lot of use.

Just switched everything over to co-alr over the last 2 months. Pricy little buggers, but a lot simpler than pigtailing which just stuffs the box.

[clare]

Ant there is aluminum wiring, and there is aluminum wiring. The early aluminum was hard and fragile. The later stuff is softer and more ductile - and a lot tougher.

As for the connections - CU-AL USED to be the accepted standard. CU-AL devices are no longer accepted. The new standard for aluminum wiring devices is coalr or co-alr

[Ralph Mowery]

YOu never know about the wiring problems. In the area I lived in there were

14 houses built arund the same time in 1965 and very similar to each other. Two of them caught on fire. One several years before we moved in and one about 10 years after we moved in.

[Nate Nagel]

that's correct, it would also need to be a 50A receptacle. You actually

*could* connect a 15A recep to 8AWG wire though - but only if the circuit were protected by a 15A breaker. You couldn't physically do it though, you'd have to pigtail the 8AWG to 12AWG or 14AWG in the box.

You might even want to do this in certain circumstances, e.g. wanting to provide a receptacle in a very far away outbuilding but not wanting to pay for another service, panel, meter, etc.

nate

[clare]

Used panels and disconnects are so cheap it doesn't make sense to do it that way in the real world though. Heck, even a 2 circuit disconnect NEW is cheap enough to run the heavy wire to the disconnect, properly protected for the 15 or 20 amp circuit you want to connect to it, making a code compliant installation. Run the cable off a double 30 amp breaker or fuse block in the main panel to protect the cable, and then fuse or breaker the disconnect for the POU load..

Other than a "lug" connector it is pretty difficult to make a good connection between a 8AWG and a 14 AWG connector. Dad used to use Burndy connectors for that. (split copper bolt and nut) KS15 or ks17/ks17-3 wrapped with tape when he needed to connect widely disparate wires. ALso work good to extend service wires when installing a new panel where the old wire is too short. (different sizes for different cables, of course)

[clare]

1965 was the old hard fragile aluminum , and there were NO wiring devices available specifically for aluminum in 1965 - not to mention most electricians had never worked with the stuff and didn't have a clue about the possible problems. By the late '60s and early seventies, the better wire came on stream, and in the mid seventies CO-ALR devices were developed and listed for use with both copper and aluminum wiring. The cu-al devices were a stopgap measure that were never actually tested and listed for Aluminum wiring, and in many cases were IDENTICAL to the cu-only devices except for the marking. CO-ALR became REQUIRED by the end of the seventies, and when properly installed on the second generation wire are perfectly safe. A lot safer than pigtailing with Ideal Purple twist connectors - and about the same price but less labour than pigtailing with AlumiConn connectors. Both are much less expensive than the AMP connectors, which are virtually impossible to get installed in most of Canada and the USA today. Special tool, leased from AMP for very high price to electricians who spent lots of money to be trained and certified in their application, and generally wanted to cover the training costs on every job. - didn't go very far....

[trader4]

No but there can be requirements as to the max allowed breaker size. Take a central air conditioning unit. Look at the install instructions and/or rating plate on the unit and it will typically spec both a min breaker size and maximum, like min 30A, max 50A. If that is part of the manufacturers install instructions I believe it would be a code violation to use a breaker exceeding 50A, no matter what size wire you use.

Also, I don't think it's kosher to change the cord and plug on any listed appliance to accomodate being able to be plugged into a higher amp receptacle. I think that is the point gfre was making with his citation of the code.

[bud--]

A #18 cord on a 20A circuit can carry enough current to trip a breaker on a fault, and is not likely to be damaged by the fault current (if the supply breaker trips). That is why #18 wire is allowed.

A #18 cord on a 50A circuit will get 6x the heat from a fault if the breaker trips as fast (and it won't trip as fast).

The size of the wire goes up as the circuit capacity increases.

UL regulations cover the air conditioner cordset and plug that are allowed.

UL will not allow a 50A plug on your 15A air conditioner. If you replace the plug with a 50A one the air conditioner is no longer UL listed.

If you read the instructions for the air conditioner it will, in all probability, give you the maximum rating for the circuit the air conditioner can be connected to. (May also be on the label on the air conditioner.) For a 15A air condtioner that will not be 50A.

UL sizes the cord and internal components based on the circuit amp capacity. If the air conditioner was intended for a 50A circuit it would not have the cord that is installed on a 15A air conditioner.

It is a violation of the UL listing. The air conditioner is no longer UL listed.

That means it is a code violation.

240.5 Protection of flexible cords... "(1) Supply Cord of a Listed Appliance.... Where flexible cord... is approved for and used with a specific listed appliance..., it shall be considered to be protected when applied within the appliance... listing requirements."

UL and the NEC work together.

The branch circuit device also protects the air conditioner.

Irrelevant.

[bud--]

Extensive testing of aluminum connections for the CPSC found that the only listed wirenut for aluminum (Ideal 65) can fail even if installed using the manufacturer's instructions.

Yes, the problems were only for 15 and 20A branch circuits.

[bud--]

The garden variety 15A duplex receptacle we use is rated 20A for both halves together and for 20A wire through. (It certainly will be used that way when connected to a 20A circuit.)

A 20A receptacle on a 50A circuit is a code violation (210.21-B-3). Should be apparent that doing the same thing bu changing to a 50A plug is also a violation.

[Tony944]

I strongly suggest to you to study Ohms Law before you start recommending powers hookups