Can you use too big a wire for a subpanel?

[crokett]

If your trenching all of this in, consider putting in an extra conduit that you can run wire thru later ( phone, cable, network, intercom, etc.)

Yup. And add some string or other line in the conduit that you can use to pull your new wire through.

[cwsmith]

Electrically, there is no problem with using a larger wire size. The larger the wire, the more amperage carrying ability it has. I believe the NEC specifications are for "minimum" wire sizes most cases.

However, there are the mechanical issues that have been previously mentioned. You need to be able to fit the lugs, bend it through conduit, etc. Heavier wire is obviously going to be more difficult to work with in many applications and in some cases, may not fit the lugs, boxes, etc.

Regarding the price of copper, has this come down a bit? I seem to recall that back in June and July a 300 ft roll of 12/2 was around $110, but I noticed last week that the same roll is now $85. (Home Depot prices.)

CWS

[BigguyZ]

Regarding the price of copper, has this come down a bit? I seem to recall that back in June and July a 300 ft roll of 12/2 was around $110, but I noticed last week that the same roll is now $85. (Home Depot prices.)

CWS

$85 is still rather high from the rolls I've previously bought... Does copper wire fluctuate like gas? Is this really something we need to look out for? I need to wire my entire workshop- and don't have too much 12/2 left....

[LCHIEN]

Here's the historical prices of copper for the last five years.



Maybe you should sell the oversize stuff and buy the correct stuff.
Then you'll have money left over and the wire will fit. Provided you can get at least 50-75% of retail for the big stuff.

[eezlock]

electrical wire size

The electrician wants to use 6-3 wire + ground for a new 60amp 220V subpanel.
No argument there. My dad has cable of unknown wire number and gauge he
used for his cabin. He says it's sized to power 200A service for his cabin.
So this cable has to exceed what's needed for my sub.

The wire going to my garage is going underground in a conduit. Can I use my
dad's extra cable for my sub? It's not possible to have too thick a wire is it
as long as it fits the lugs in the sub?


Thanks, Paul

Paul, there should not be any problems using the larger size of wire except putting it into the panel main lugs.
The rule in electrical wiring is...you can underfuse a wire/cable, but never,
never, overfuse a wire. Example: #10 gauge copper is rated/good for
30 amp breaker....but can be fused at 20 amps if you only need a 20
amp circuit. Hope this helps. eezlock

[Jnam]

(Not intending to hijack this thread)
I caught the tail end of some CNN news a couple of days ago. One of the newscasters said "what a shame it was that some people have taken to stealing other people's outside AC unit for the metal". That is all that I heard.

Was it copper that they were talking about? Has copper gone that high?

I dont want to high jack it either, but here in Florida a guy was arrested and convicted of stealing electric company cable at new construction sites,...he was taking it out of the ground!

Dressed as a service man he had his truck loaded with wire he had been taking.

[Wood_workur]

well, as long as the wire will fit the lugs when divided , you will be good. the way the wire fits the breaker is a clamp that looks like a small m, and will hold a good bit of wire.

[dick541]

Watch out: Back in 1981 I put in a new service in my house. I used #00 wire that was covered with a thin clear plastic cover from the meter box to the ground rod. The inspecter came and made me replace the ground wire because it was TO BIG, I had to replace it with #6.

dick541

[HarmsWay]

Both threads here are quite interesting. I'm not qualified to comment on NEC rules and intent but... in the local news a couple of weeks ago, the police and power company were asking people to watch for anyone burning a big pile of cable. Apparently thieves made off with more than a kilometre of active power line right off the poles.

Edit-> Took me forever to find the article (not too news worthy I guess, which says something).

http://ladysmithchronicle.com/portal...d=726045&more=