Multi runs versus sub-panel

[jdub63]

My main breaker panel (200amp) is on the opposite side of the shop from the 220 compressor, a 220 exhaust fan, and a 220 waterheater. My question is, should I run three different circuits from the main panel or one circuit to a subpanel with shorter runs to each load? I'll have to verify, but I think a 100 amp subpanel would support. Each load is around 30 amps (except for the compressor start-up).

 

[nehog]

Either would work. In my case, I have tons of 12 AWG wire, so I'd run three circuits. If I had no wire, I'd check to see if there was a significant price advantage of a sub-panel. Remember that you need a breaker in the main panel to feed the sub panel (to protect the wire run), and that would be a more expensive high amperage breaker. And the cost of the sub-panel (some are not that expensive, but added to everything else...).

Main advantage of the sub panel? More expansion options in the future not having to run additional wires from the main box! So if you add a welder, or something else big, a sub panel will allow easier expansion. But there's an alternative: you can run extra circuits in advance and just not use them.

Also, just a bit of advice: if you do use sub-panel(s) label every box/outlet, and switch to identify which panel serves it.

 

[Falcon67]

On a smaller scale, I'm going to do this for the kitchen remodel. It's easier to bring a 6/3 w/ground to a small 6 breaker panel over the kitchen than try and fish 5-6 wires though that same bitty attic space near the box (my bad for not pulling more spares in larger conduit when I installed the box outside!). It's all lighting, vent, disposal and counter plugs - nothing heavy duty like an electric range.

For my deal, 55A 6/3 cable at Lowes is 2.32/ft, so with the box I'm looking at maybe $100~120. That's more $ than snaking 5 runs of #12 through all the junk up in the attic, but 10X less hassle for running circuits during the remodel and less clutter in the outside panel.

For a 100 amp deal, probably looking at #2 at around $2 a foot per cable with three #2 and a #6 or #8 (better look all that up in the book) ground. Anyway, compare that cost of the feed plus the panel to three 30A breakers at $5~10 each plus three runs of #10.

I am considering the same thing when I get my little addition built on the shop. There will be at least 2 30A/220V conntections in there plus 2 or 3 15A 220V hookups.

 

[jvitez]

Our 3 year old house has two 200 amp 40/80 Siemens panels, 400 amp service. The electrician considered putting the second panel on the other side of the house fed as a sub and running half the circuits from there, but decided it was cheaper to have both panels together. Hence, I've got this sloppy mess of wires running all over the place in the mechanical room. I would have much preferred his first idea. It would have been easier for me to run the circuits I want for my basement wood shop and garage project. Live and learn. Each of these is getting a sub panel for exactly that reason.