Wire Size Chart ?

[Tom from Buckeye Lake]

Can someone point me to a site for a wire size chart? I know that length of run from breaker is also a factor.

Wanting to supply 50 amp/220v service to garage underground in conduit.

A chart for future reference would be nice.
Thanks, Tom

 

[John T]

Try this:

http://www.powerstream.com/Wire_Size.htm

Without looking a the chart No 6 copper is probably in the range youre lookin for, even bigger depending on the distance ???????????????(I should go look first lol my memory is gettin worse daily)

For 120/240 volt service run 2 Hots (L1 & L2),,,,,1 Neutral,,,,,,,,,1 Equipment Ground Conductor.

Do NOT bond Neutral and Ground busses at garage sub panel

Do drive a ground rod or rods as required for grounding electrode(s) in your local authority jurisdiction at the garage.

John T

 

[Pete_5959]

Tom,
I ran the direct bury cable offered at Lowes. It is alum 4 conductor #6. Used primarily for mfg home hook up. Although it is direct bury I opted to use schedule 40 conduit as the cost is relatively low. My run is 70 ft and I am running a 70 amp service. I think the standard is 28 inches deep.

Pete in NC

 

[Awlknottedup]

Has anyone noticed the price of copper lately? I bought a 100' roll of 12-2 a couple of months ago and if I remember correctly is was around $35 a roll. I bought another roll Saturday and it was $57.


I also picked up 45' of 8-3 for $107.

 

[PKurilecz]

#6 Cu may be adequate to about 125 ft run length. Beyond that, #4 Cu may be adequate to about a 225 ft run length.

It may be less expensive to run THHN conductors inside PVC conduit than to run direct burial cable. I recently priced a project to run power to a small group of out buildings, and I found that the conduit option was significantly less than direct burial cable.

Be sure to follow jurisdictional requirements and NEC requirements.

hth

pkurilecz

 

[John T]

It may indeed be a cheaper way to go as that conduit is fairly cheap. As I recall (its been yearssssssssss) I specified TWWN insulated Conductors (instead of THHN) for those underground in conduit wire runs. If he goes under driveways he ought to be using conduit anyway.

John T

 

[Dusty MI]

I would consider to over size the conduit. The wire will pull easier and some day you may want a larger panel out there.

Last I knew THHN and THWN is the same type wire, it just depends how it's used.

Dusty

 

[rubberwrench]

Look for a Ugly electrical reference book .Will have all the information you need

 

[36 Coupe]

Aluminum cable does break often under ground.

 

[david - or]

THHN amd THWN are NOT the same. THHN is not rated for wet locations, and underground conduit is considered a wet location. The insulation on THWN is thicker in diameter than THHN, and you can't fit as many wires in agiven size of conduit.

That said, a fair amount of wire out there is dual rated as THHN and THWN-2. This wire has the same diameter as THHN, and is also rated for use in a wet location, by virtue of the "THWN=2" stamped on the insulation of the wire. If you handle this type of wire you can see the extra clear plastic jacket over the colored thermoplastic insulation. You have to handle such wire with reasonable care, or you'll abrade or cut the clear jacket and lose protection build into the THWN-2 rating.

 

[John T]

Like I posted below I recall specifying THWN (NOT THHN) when we ran wire in underground conduit etc but inside dry building locations we used THHN instead. Problem was that was so long ago I done forgot all the different insulation ratings but thats information thats readily available.

Thanks for the info

John T

 

[Tom from Buckeye Lake]

Thanks for the replies. I knew this was the site to ask for answers!! Great response.

 

[PKurilecz]

Went to the big box store today to check the insulation ratings on the #6 and #4 stranded.

Both were marked THHN and THWN.

Thank you for bringing up this detail.

pkurilecz