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-   -   220 Volt Wiring size? (http://www.diychatroom.com/f18/220-volt-wiring-size-25363/)

helpless handyman 08-18-2008 08:03 AM

220 Volt Wiring size?
 
I am in the stage of closing my walls in a basement renovation. I want to run some bx cable and leave it behind the wall for future use, if basement is not warm enough with the insulation. I need to know if 12/2 would do for a 25' run for a 220 volt circuit, or do I need 12/3, 12/4? I will not be doing the install, but rather have the wire inside the wall for future use. This will be for baseboard heater.

Thanks,

buletbob 08-18-2008 08:18 AM

I personally would run the 12/3 this way if the heat is not needed, you have the option at a later time to run two 15 or 20 Amp 110v circuits when needed. And you still have the option for the heat circuit if needed. GOOD LUCK BOB

rjniles 08-18-2008 08:23 AM

Quote:

Originally Posted by helpless handyman (Post 149593)
I am in the stage of closing my walls in a basement renovation. I want to run some bx cable and leave it behind the wall for future use, if basement is not warm enough with the insulation. I need to know if 12/2 would do for a 25' run for a 220 volt circuit, or do I need 12/3, 12/4? I will not be doing the install, but rather have the wire inside the wall for future use. This will be for baseboard heater.

Thanks,


25 feet is not a problem. 2 wire cable is fine for base board electric units. 12-2 (20 amps)can supply up to a 4400 watt heater, if you plan on something bigger go with 10-2(30 amps). Run the cable from the cicuit breaker panel to the heater location. Also run a second cable of the same size (from the heater location) to the thermostat location (most baseboard electrics use line voltage thermostats). I would also run a low voltage thermostat wire (3 wire)to parallel that second wire just in case. Unless it is not allowed in your locality I would use NM (Romex) cable, it is cheaper and easier to handle.

helpless handyman 08-18-2008 08:25 AM

Thanks BuletBob:thumbsup:, sounds good!

helpless handyman 08-18-2008 08:28 AM

Thanks Rjniles:thumbsup:. Almost forgot that run to the thermostat!

Speedy Petey 08-18-2008 03:31 PM

Quote:

Originally Posted by rjniles (Post 149599)
212-2 (20 amps)can supply up to a 4400 watt heater,

A 20A 240v circuit for electric heat can supply 3840 watts, NOT 4400 watts.

Electric heat shall be considered a continuous load; which is 80% of a circuit, or 125% of the load.

petey_c 08-18-2008 05:46 PM

hh, What rjniles and Speedy Peety are saying is good advice. Work backwards. Figure out how big of a heater you'll need, then run the correct size wire. You can also mount a thermostat directly on the heater (unit stat). I prefer a wall mounted t-stat.
I don't like to run a 3 wire for two separate circuits. There's always a possibility for too much current to try and get back to the panel on a small neutral. For arguement's sake, 13 amps on each of the "hots", that means 26 amps coming back to the panel on a single 14 ga. wire. Which is only rated for 15 amps. Most cases it would probably never happen, but you should always err on the side of safety. pete

chris75 08-18-2008 05:53 PM

Quote:

Originally Posted by petey_c (Post 149761)
.
I don't like to run a 3 wire for two separate circuits. There's always a possibility for too much current to try and get back to the panel on a small neutral. For arguement's sake, 13 amps on each of the "hots", that means 26 amps coming back to the panel on a single 14 ga. wire. Which is only rated for 15 amps. Most cases it would probably never happen, but you should always err on the side of safety. pete

What the heck are you talking about? If you had 13 amps on each leg, the neutral would read zero....

junkcollector 08-18-2008 06:17 PM

Probably a better argument for not using a multiwire circuit is the use of AFCIs.:thumbsup:

Speedy Petey 08-18-2008 06:27 PM

Quote:

Originally Posted by petey_c (Post 149761)
I don't like to run a 3 wire for two separate circuits. There's always a possibility for too much current to try and get back to the panel on a small neutral. For arguement's sake, 13 amps on each of the "hots", that means 26 amps coming back to the panel on a single 14 ga. wire. Which is only rated for 15 amps. Most cases it would probably never happen, but you should always err on the side of safety. pete

Wow!

Petey, please be careful giving advice such as this. You are 180 degrees off on this as Chris stated.

Be sure what you are saying is correct and code legal. This can be pretty important stuff here.

chris75 08-18-2008 06:27 PM

Quote:

Originally Posted by junkcollector (Post 149776)
Probably a better argument for not using a multiwire circuit is the use of AFCIs.:thumbsup:


most electric baseboard heat is 240v anyhow....

junkcollector 08-18-2008 08:31 PM

Quote:

Originally Posted by chris75 (Post 149780)
most electric baseboard heat is 240v anyhow....

I know.:) I was talking about:

Quote:

Originally Posted by buletbob (Post 149597)
I personally would run the 12/3 this way if the heat is not needed, you have the option at a later time to run two 15 or 20 Amp 110v circuits when needed. And you still have the option for the heat circuit if needed.

Sorry I should have been more clear.

chris75 08-18-2008 08:42 PM

Quote:

Originally Posted by junkcollector (Post 149808)
I know.:) I was talking about:



Sorry I should have been more clear.


Not your fault, I didn't see the part you highlighted.

theatretch85 08-19-2008 12:25 AM

I guess petey_c has never heard of a Multi-Wire Branch Circuit before?

It would be a good idea that in the event you don't need the heat (since it seems you currently are not sure whether you will or not) preparing for it with a run of 12/3 or 10/3 now would not be a bad idea. Could give you those two dedicated circuits for a home theater or simply allow for a small plug-in heater for the really cold days.

You wouldn't need the neutral wire if you use it for baseboard heat, but its one wire that would be "extra" in the event you do actually put in the heaters (rather than wishing you had pulled it earlier).

helpless handyman 08-19-2008 08:53 AM

Thanks to all you guys for the quick reponse and the geat ideas. I had plenty of 12/2 left from the reno, so I decided to run two dedicated lines just in case. I know the 12/3 would have been good, but would have to go out and buy it. I used what I had. Thanks so much to all..:thumbsup:


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