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-   -   Aluminum wire size/ guage / amps? (http://www.diychatroom.com/f18/aluminum-wire-size-guage-amps-24386/)

walt1122 07-28-2008 11:14 AM

Aluminum wire size/ guage / amps?
 
Hi all two questions. Have a roll of aluminum wire but can't read the size. I'm getting about .240 inch per leg. Having trouble finding a chart that tells me size in aluminum, copper yes, aluminum no. Know where I can find one or got any idea what size this might be? Also there are some abrasions on the outer skin and a couple breaks/tears to. Nothing into the sheathing of the wire but is this a problem, can it be fixed so the I can use it and not have a problem with inspectors. About 150 feet of wire and I need some of it for my HVAC ( new construction) for the heating element. Probably needs to handle 5k or might use 8k if it turns out to big big enough to carry enough amps.

thanks for any help or suggestions

Walt

handyman78 07-28-2008 11:21 AM

Gauge would be the same for both copper and aluminum- the difference is the amount of amperage it can carry. For service entrance conductors aluminum is usually 2 gauges larger than the same in copper.

walt1122 07-28-2008 11:54 AM

Hi handyman78, thanks but I think I'm looking for something a little more definitive. I understand that the guage would be the same but it is what the carrying capacity of the aluminum wire would be based on the size of the wire AND if there is an issue with the tears in the exterior grey plastic sheathing even though there aren't any breaks in the individual wire coatings. I'm trying to do alot of this work myself prep the HVAC and electric service for the contractor so I can maybe keep the prices down. If I can supply the wire that should be a savings. I have had this wire around for years but I would like to use it instead of scrapping. But only if it doesn't cause issues with the inspector.

thanks again

Walt

Yoyizit 07-28-2008 01:02 PM

Quote:

Originally Posted by walt1122 (Post 143733)
I'm getting about .240 inch per leg.
Also there are some abrasions on the outer skin and a couple breaks/tears
Probably needs to handle 5k

240 mils = 240^2 = ~57,600 Circular Mils.
My wire table shows 52,620 CM for #3 and 66,360 CM for #3.
Another wire table for [probably] solid wire shows 66370.0 CM for #2.

Isn't the cable marked? If a manu part number is on the cable, Googling it might come up with the specs on this cable.

By the way, #2 is twice the CM of #5 is twice the CM of #8, and so on.

Moisture is the enemy of cables once it's inside. Openings will allow water to wick in [by Capillary Action], even against gravity, and eventually destroy the cable.

5k watts? At 240v?

walt1122 07-28-2008 01:29 PM

Hi Yoyizit, please clarify
"My wire table shows 52,620 CM for #3 and 66,360 CM for #3."??
Which number is wrong! and can you tell me how many amps can each of these wires carry?

Yes, haven't done the complete calculations yet but I'm thinking I need at least 5k watts at 240V and might need as much as 8k @ 240V. to give me the BTUs/H I will need. Just trying to find a use for the wire. I have some kind of mold/dirt along the entire length of the wire. I have tried everything to clean it and the only way is to scrub it with 3M scotch pads and I'm either removing the AWG wire size info or it has come off on its own. If it is the right size it will be used indoors.

thanks

Walt

Yoyizit 07-28-2008 02:01 PM

Quote:

Originally Posted by walt1122 (Post 143770)
Hi Yoyizit, please clarify
"My wire table shows 52,620 CM for #3 and 66,360 CM for #3."??
Which number is wrong! and can you tell me how many amps can each of these wires carry?

Yes, haven't done the complete calculations yet but I'm thinking I need at least 5k watts at 240V and might need as much as 8k @ 240V. to give me the BTUs/H I will need. Just trying to find a use for the wire. I have some kind of mold/dirt along the entire length of the wire. I have tried everything to clean it and the only way is to scrub it with 3M scotch pads and I'm either removing the AWG wire size info or it has come off on its own. If it is the right size it will be used indoors.

thanks

Walt

That's the problem; I don't know which number is wrong/right, and they can't both be right if they are one whole gauge number off.

The amps a wire carries depends on ambient temp and what insulation it uses. Power lines across the country get up to 100C.

Yeah, use the wire inside.

Electricians do this calc every day of their lives; I hope one of them answers.

I can probably step through this procedure using my 1999 NEC interpretative book by Mr. Mullin. Otherwise the volts, amps, wire temp and voltage drop all chase each other around forever. And, it's not just Ohm's law; you need to follow safety rules.

But, if you come up with the length of wire that you're using, the wire insulation type, the current draw (max and steady state) of the load I can tell you how it will perform, based on Ohm's law and accounting for conductor temp.

Don't put any more labor into this cable.
You can also use it for jumper cables, but you need those humongous alligator clips.

Stubbie 07-28-2008 02:07 PM

My advice for what it's worth. I would never use 'used' (obviously questionable) wire INSIDE my home or for new construction.

You are prone to many errors trying to figure out what wire you have without identification on the outer sheath. You could have wire/cable not approved to enter inside a building.

You also don't mention what you are measuring just the bare wire or bare wire and insulation or what?

Don't use it and you can sleep at night.....

wire_twister 07-28-2008 02:28 PM

I agree 100% with Stubbie, it would be hard for me to sleep in a house with wiring I was not sure about. Sell it for scrap and get a piece of copper wire for your heat/ac. Post back with the amperage requirements of both air handler and compressor and we can tell you what size wire you need.

walt1122 07-28-2008 02:39 PM

thanks guys, bare wire only no insulation. Just looks bad have XHHW #6 just like it I took down ar the same time when we shut down facility and moved business South. Just can't remember what piece of equipment it powered. The #6 is maybe 50% smaller. Just trying to make use of the wires the larger is dirty and having trouble cleaning. I just thought I could find an easy way to determine if it is viable before I waste too much time cleaning it if the cuts will be a problem with the inspection and or if it isn't large enough to carry the amps I need.

Walt

Stubbie 07-28-2008 03:03 PM

My guess is your inspector might turn it down.... and will turn it down if he looks past the terminations for the insulation identification due to its appearance.

Take it to recycle and spend the money on new wire.

If your hell bent on using this stuff here is a size chart my guess is #2 or #3 al. #2 al is 75 amps and #3 al is 65 amps. These are the ampacities for insulated wires with 60C insulation.

http://www.litz-wire.com/wirediminsions.html

But inspectors don't catch everything so I'd be real freakin sure what you have there or you may be sleeping under the stars.

stubbie

walt1122 07-28-2008 03:41 PM

thanks Stubbie for the chart and thanks to everyone for their input. Based on the issues I probably will have to forget this and just rethink the whole thing. Wire_twister I'm still trying to get a reliable heat load calculation so I can figure out what size system I need. The contractor I had said I needed a high end 2 stage 2 ton heat pump but when I asked him for his Manual J calculations he said he didn't need to do them cause he KNOWS what I need. Well I had him do the calculations and the system is way, way to big for the 3 car garage w/apartment above we are building. Plus he put in a crappy duct system so I fired him. Soon as I know what size system I really need I will come back and ask you all to help size the wire and breakers.

When I did this house I had to put in two disconnects at the airhandler. Think they were a 60A? and a 90A for a 6 ton geothermal heat pump with 15k? electric backup. Is this the normal way to handle? Ran copper wire through conduit so I might do the same thing in Tenessee cause they already put up the sheetrock in the garage before I had a opportunity to get down there from our home in New Jersey. Probably easier that breaking through walls. what would you guys suggest??

thanks

Walt

Stubbie 07-28-2008 04:21 PM

Wise decision making Walt. It is normal to have disconnects at airhandlers and heat pumps. Often times backup heat if electric has supplemental overcurrrent protection (breakers) on the equipment. Then you have an ocpd's in the main panel or sub-panel. So it is hard to advise without knowing what the equipment is, we can give wire sizes and ampacities given the nameplate information but it is really adviseable to have the manufacturers instructions in your hand so you can view the wiring schematic and design.

Yoyizit 07-28-2008 07:52 PM

Quote:

Originally Posted by walt1122 (Post 143805)
The contractor I had said I needed a high end 2 stage 2 ton heat pump but when I asked him for his Manual J calculations he said he didn't need to do them cause he KNOWS what I need. Well I had him do the calculations and the system is way, way to big for the 3 car garage w/apartment above we are building. Plus he put in a crappy duct system so I fired him.

If you're going to spend kilobucks I'd get at least 3 estimates.

walt1122 07-28-2008 10:10 PM

that's exactly what I told my builder as he gave the work to his buddy. I said get me some more quotes cause his price sounds high. And i was right. He wanted over 8 grand for this system. Couple of 14 inch round main ducts down the length of my garage ceiling dropping what was a nice 10 foot ceiling down to 8 feet when they get boxed in. Pissed me off cause he wasn't even supposed to be doing the work. But because my builder gave him the go ahead I felt responsible and paid him for what he did. Cost me 2,500 bucks for something I can't wait to tear down and replace with some rectangular 8 x 24 or so that he should have put up in the first place. At least I didn't get caught for the other 5,500 for the heat pump Can't wait to get rid of this builder been nothing but bad since I hired him. Got great recommendations but I don't know how!

take care

Walt

theatretch85 07-28-2008 11:15 PM

I understand you probably won't use this wire anyway, but .240 inch sounds like #6 wire, and in aluminum it would only be good for about 40 amps. I have a bundle of #6 4 conductor aluminum here, probably pretty close to the same stuff you have (it has a gray outer sheath).


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