Hi,
I am ready to run a line to my work shop (6/3 thhn, 100 feet, in conduit at a minimum depth of 18in) and have a question about which panel box to run it from.

I have a line running from the meter to an outside 200amp main breaker box and then from there to my main 200amp breaker box in the house. This was done when the house was installed (modular home) by an electrician and it was approved by the inspector.

I have a 125amp main lug box in the work shop. Should I feed it from the inside or outside panel? I will be installing a 50amp switch in the panel feeding the work shop panel. Does it make any difference which panel I use?

Thanks in advance for your help!

 

If there is space to do so, you should run it from the closest panel to the meter, which I believe is the outdoor panel by your description. If you have to use the other panel instead it's not a big deal.

If you use THHN in conduit you need 2 #6 hots (black or red), 1 #6 white, and 1 #10 green ground. You could use up to a 70A breaker in that case. The 6/3 cable you mention is a direct burial assembly not normally put in conduit.

The main lug panel is only allowed if there are 6 or fewer breakers in the work shop panel, otherwise a main breaker must be included.

 

It would be unusual to have a 200 amp main breaker panel outside unless it has feed-thru lugs to feed the inside panel. Is it a breaker panel or just a 200 amp breaker disconnect serving the inside panel? If it is a panel and will accept additional breakers, that is the best one to feed the shop from.