Rerout'n 220 to Shed

[Poncho]

Plan'n on 2 Splices in #4 Alum UF 220 v Cable, each joint in above ground J Boxes for Reroute from under Deck to around new Patio. Will use Compression fit and J boxes will remain accessible. Total wire length is 125 ft, go'n to 60 amp SB. Sound OK ??
Also, how close to the Sub Panel for the 60 amp Disconnect ?

 

[Reach4]

You want to post wire length and the load. Are you feeding a 40 amp subpanel, or what?

 

[Sponsor]

 

[hj]

What's a "40 amp SB"?

 

[Reach4]

https://www.cirris.com/learning-center/calculators/133-wire-resistance-calculator-table says 230 ft of #8 would have 0.144 ohms. I used 230 ft as 2*110 plus an extra 10 for etc. With 40 amps, that would be a voltage drop of 40*0.144= 5.76 volts. For a maximum of 3% voltage drop, a 120 circuit could have a maximum drop of 3.6 volts. So no go for a 120 volt load or a subpanel that includes 120 volt loads, unless the 3% does not apply.

For a 240 only load system, the maximum drop permitted would be 7.2 volts. So the #8 would be OK.

I am not an electrician. It may be OK to have a bigger drop, and with a breaker panel where the 120 volt load are balanced moderately well, I think you would be fine in practice. I am not an electrician, and maybe the 3% drop was too severe of a standard.

 

[Poncho]

What's a "40 amp SB"?

Sub Panel

 

[Jadnashua]

The utilities sometimes use a smaller gauge supply drop than is allowed after the panel, probably because it can handle the heat better while strung through the air. That's not the case when you bury it, or enclose it in a wall.

 

[Norcal01]

The utilities sometimes use a smaller gauge supply drop than is allowed after the panel, probably because it can handle the heat better while strung through the air. That's not the case when you bury it, or enclose it in a wall.

PoCo's are under different rules that do not apply to the customers premises.