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Question - Adding 220V and 110V circuits to garage

I want to add two 220V and some 110V outlets to my garage. The wall where I want to add them is far from my breaker panel (at least 70 feet) but is close to my meter. There is even a box with a removable panel on the inside wall right behind the main service box that provides access, from the inside the garage, to the house's main 400A breaker in tne meter box.

I would like to install a breaker box with two 30A 220V and two 20A

110V circuits and connect right to the main service box (after the main 400A breaker of course). This would save me from running a long run from the distribution breaker panel, where I don't have enough room anyway.

I have done a fair amount of home wiring and am pretty handy with this, but I have never worked on mains side of a distrubution or breaker panel. I don't want to mess this up, so I have some questions. When I look at the main 400A breaker and the buss bars coming from the meter, I don't see a neutral line.

There are two large hot wires that pass through a 400A ganged breaker in the main box, and a green ground that looks like it only goes to earth. My questions:

1) Is it OK to connect my new panel right to the 400A breaker in the main box?

2) How would I wire the 110V circuits? I know that each hot end of the

220V feed (through an appropriate breaker in my sub panel) will be a 110V hot, but where are the 110V neutrals? Do I simply run two wires back to the green in the main service box and call one "neutral" and the other "earth"?

3) Is it typically OK code-wise to split up the output from the main breaker right in the service box? I doubt they make wire nuts that big and I don't think it's OK to "double up" wires on a breaker, so if it is OK, how is done? Do they sell monster terminal strips?

To diffuse all the safety related replies I'm likely to get, let me say that I'm incredibly careful around wiring. If this seems too much for me, I will certainly hire an electrician. But if the answers are not too intimidating, I'd rather do it myself - not to save money, but because 1) I have found that I am more careful and do better work than the trades people I've been able to hire, and 2) Where I live, you can't get people to show up for small jobs. It will take a least a month to get this done by an electrician and I'd like to start welding now.

Reply to
lens
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A 70 foot run to a subpanel is no big deal if you use the right size wire to limit voltage drop. You can't really connect to the 400 A breaker. It's not practical in a residential installation and certainly not desirable. I think you're a bit beyond your DIY capabilities here. You have a 400 amp service and you don't have two spaces free in your distribution panel? Most houses with 400 amp services have panels and subpanels galore.

Reply to
ATP*

In theory anything involving the feed into the subpanel needs an electricians inspection to be carried out why not just add in a 100 amp double in the main panel and that will give you "240 duplex or however you want to call it at 100 A. INstall another 100A breaker in the subpanel and run the cable.

Always overestimate the cable size you need by a wire gauge. the cheapest insurance on earth against home wiring is just that for the extra 20 cents per foot you might pay to increase the wire gauge 1 or 2 sizes think of the headaches it solves.

And a run form the main panel to a subpanel is just another line to a stove that dumps into a subpanel and is not past a home wiring job

Reply to
Brent Philion

Not an electrician's inspection, an authorized inspection agency/company. Inspection requirements vary by municipality.

why not just add in a 100 amp

Unless you need a local disconnect for the whole panel, a main lug subpanel would normally be employed with a separate ground bus not tied in to the neutral.

95% of home wiring jobs, even by electrical engineers, are butcher jobs because the homeowner has never spent a day working for a professional electrician and has no clue how to route wire, how to secure wire, etc.in a workmanlike fashion. It's not all "common sense". That is not to say there aren't professional butchers out there as well.
Reply to
ATP*

Thanks for the repies. It now *does* seem easier to make the 70 foot run back the breaker panel. It turns out I do have room in the panel. It was full of breakers, but at least 3 are unused. This leads to another question. I'd like to use the 2.5" conduit that holds the main feed from the entrance, to carry a 100A line that I run back to a garage sub-panel, but I am told that this is not allowed (i.e. that conduit can carry ONLY the entrance lines). Does that seem correct? If so then I have to run another conduit, which will be a pain. The guy who told me this suggested I put a another big subpanel in the garage and run the main feed straight to that. This would take about 2 feet of new wire. The new panel then feeds the rest of the house on the old main feed wires (which I drive from the new sub-panel) and also houses breakers for my new garage outlets. This means I have to move some big wires a short distance, but I don't have to do any long conduit runs. Does this sound reasonable?

Reply to
lens

A few potential issues there. The current panel will be too big to run as a sub off any reasonably sized new panel. There are limits as to how much current can be drawn off the breaker stabs. I wouldn't try running essentially your whole house off a two pole breaker in a subpanel. There are potential ways around it, but without seeing the actual installation I shouldn't really comment further. Unless there is some almost insurmountable barrier to running a line to a subpanel I think that's the practical way to do it.

Reply to
ATP*

Reply to
Robert Ball

Here is a closeup of the main breaker.

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The breaker reads 200A twice and the red and black pairs are paralleled after leaving this breaker, so I assumed 400A service, but I think I may be wrong. The fine print on the breaker label also shows outputs paralleled. Is that normal? Do I really have 200A service?

Reply to
lens

Totally different scenario than a residential panel with breakers that slide or push onto a thin bus stab. The main breaker in a panel is fed directly by the feeders.

Reply to
ATP*

You have 400 amp service. Those paralleled conductors go into only one panel? The setup we used to do was paralleled conductors into side by side

200A panels.
Reply to
ATP*

Re: "....we used to do was paralleled conductors into side by side

200A panels."

When I had aluminum wire running from the main to two breaker panels, that may have been what I had. Then I had the feed changed to copper, Now it's one run with 0/4 that goes to a panel elsewhere that separately feeds the two old panels, plus some newer stuff. Do you think it was "to-code" to parallel the outputs of my main breaker like that?

Reply to
lens

0/4?

that goes to a panel elsewhere that

I haven't been involved in residential services for a while. There is nothing wrong with paralleling conductors as long as all of the rules are followed. It's done all the time to economize on copper and also to keep wire size manageable, especially on larger installations. The following article gives some general guidelines:

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Reply to
ATP*

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