To Subpanel or Not to Subpanel, That is the Question

finnimus · 02-28-2009, 08:58 AM

I am in the process of planning our my electrical upgrade. We have a main panel on one side of the house, and we have a sub panel about 30 feet away in the garage. With the main panel upgrade, I will have enough space for all of the circuits on one panel. We need to replace the sub panel because the current location/setup is not up to code.

I am trying to understand if it's best to put all of the circuits on the main panel or still use a sub panel setup. If we use a sub panel, we will have: garage outlets (4 outlets, 2 lights, 20 amp), hot water heater (20 amp (I think)), dryer (30 amp), bathroom (GFCI 20 amps), and 2 bedrooms (6 outlets, 2 lights, 20 amps). If we do not use a sub panel, I will end up using conduit from the main panel to the garage to a large junction box to power all of the circuits.

I've had 2 electricians come out already and give me estimates. One suggested running conduit to the J-box and another recommended a sub panel. Your thoughts are appreciated.

AllanJ · 02-28-2009, 09:37 AM

Water heater and dryer together, and I suspect a washing machine is out there too, suggest to me that a 60 amp subpanel and 6 gauge wire is going to be marginal.

A typical water heater draws about 19 amps. Since this is a continuous load, the circuit has to be rated 25% more and the next size is 30 amp (10 gauge wire).

If a garage is a separate building, a subpanel is required for the loads you have given since only one feed cable can be run. Otherwise it is your choice to string all of the individual garage circuits as home runs.

J. V. · 02-28-2009, 03:11 PM

Whats wrong with the existing sub panel? Can it be straightened out and used? I would keep the sub panel. If you move everything to the main panel, you have to get all the circuits in the sub back to the main. You could use the sub panel as a junction box and connect the branch circuits back to the main in there. You could remove all the guts and make it a large J-Box. I would keep the sub even if I had to replace the panel and feeder. Sub panels are convenient.

finnimus · 02-28-2009, 07:08 PM

There are a few problems with the existing sub panel. First, it only has space for 4 single pole breakers. The hot water heater and dryer are hooked up to it now, so it's all full. Secondly, it is located above the hot water heater and is not easily accessible. It should have never been put there because it doesn't have enough clearance. Third, it is tapped off of the main, so it is effectively a second main panel. There is no central power shutoff for the house. In fact, I have 3 panels that are tapped off of the main. All of that will be fixed with the rewire, regardless of whether or not I use a sub panel.

The other circuits I mentioned in my first post are ones that I am going to add/separate. Right now, the bathroom, garage, and 2 bedrooms are on the same circuit with a number of other items and it is coming off of the house's main (largest) panel.

Basically what I'm trying to figure out is whether or not the additional cost of the sub panel is worth the convenience. Or maybe it will be cheaper in the long run compared to the price of the wires I would have to run in conduit.

Thanks for the responses so far.

Quote:

Originally Posted by AllanJ

If a garage is a separate building, a subpanel is required for the loads you have given since only one feed cable can be run.

AllanJ, I wanted to clarify that the garage is attached.

J. V. · 03-01-2009, 12:25 PM

Only you can ultimately decide if you need the sub or not. Since the the garage is attached you will want to bring all the old wiring from the old sub to the new main. (Lots of work) Or replace the sub and install it correctly.
Panels are cheap and wire is getting MUCH cheaper.

Scuba_Dave · 03-01-2009, 01:25 PM

I'd run the sub-panel myself
I'm debating on if I want 1 or 2 sub-panels with my addition

finnimus · 03-02-2009, 08:28 PM

Thanks for the replies. I think I'm going to end up adding a sub panel. It's just easier for me that way. I've had 4 electricians at the house in the last week, all pretty much noting the same code violations and things that need to be changed. Unfortunately, this project has expanded to include a tree trimmer and a vinyl siding guy.

All of the electricians have complimented my knowledge of what needs to be done and how it should be done. Thanks to everyone on this board for answering my questions and taking the time to answer all of the other posts. It's been a great learning experience so far.

jimmy21 · 03-03-2009, 12:21 AM

i prefer sub panels in the garage. Makes for adding stuff easier in the future

boyfly · 03-05-2009, 03:32 PM

I had sort of a related situation, and I chose to get rid of the subpanel and go with a junction box. Did the install last weekend. I put some pictures up here if you want to see what we did... ended up being 16 runs of romex from the junction box to the new main panel. I had the conduit up before hand, but wiring the junction box took more time than I expected.

Here is the junction box I used.