Yes, but your only talking maybe 20-30 watts at maximum power, less all the other time in differences.

The real question is WHY the skimped on the third home-run .... heck YOU paid for it .. its maybe 40 bucks worth of wire for anothr home run of 10awg

Maybe it requires the next size conduit for 6, #10 wires, and 3/4" is too hard for them to bend

My thought, too. The reply I got was that the extra run would be harder to pull through the conduit (they used 3/4"), also the grade of wire can handle much higher amp loads, etc.

They say this is how they generally do it, and it works fine for all the other installs (this is a major brand name company). Honestly, if I had known they were planning this I would have stopped the install and had them pull 3 home runs, but it is in now so that is the way it is.

Thanks for all the replies.

I'd make them run a second conduit and pull another home-run ... just because they made a poor decision doesn't mean you should just agree
to it ... I think they know they did it wrong and figured the home-owner would never know for the wiser.

By the way, 10 guage is standard for a single home-run, not an upgrade for doing the parallel BS.

now my curiousity is peaking here. just how long is the run of wire and is it all #10? if those losses are very much i too would agree that their shortcut is costing you power needlessly to save them a few $. look over the conract too if you have one to see if they specified that shortcut in there.

A quick check of the NEC reveals the following:

#10 RHW-2 OR USE-2 (without the outer covering):
3/4" EMT or PVC Sch 40 = 6 conductors
1" EMT or PVC Sch 40 = 10 conductors


#10 THHN:
3/4" EMT = 10
1" EMT = 16

3/4" PVC Sch 40 = 9
1" PVC Sch 40 = 15

You should also have a ground wire (#10) in the conduit.
If THHN is used, it must be terminated in an enclosure.

well after my making a fairly big stink about it, my installer agreed to pull an additional home run so that I will not need to combine strings on a single 10AWG circuit.

Thanks for all the feedback from everyone on this...hearing the strong opinions from this community was a big part of why I decided to push hard to have it redone correctly.