Power to garage

[Andamo]

I ran into a problem yesterday while installing a garage vacuum. I had to run wire (14-2) from a end of run box over the garage door and install a plug for the vacuum. I just wanted to check the live box, and when I did, it arced against the side. My power for these wall boxes comes out of the main panel in the garage and then goes through a GFCI so that all the wall plugs are protected by the one GFCI. I reset the GFCI after the arc in the box and finished up the plug for the vacuum. After I was done I flipped on the breaker and I thought all was good. But later I noticed that the upstairs lights along with the wall plugs and outside lights were off. I got to looking and checking and I now only have 110v coming into the main panel on the one wire. The other wire is dead. These 2 wires come from the house underground and go into the garage panel into a 100 amp breaker.
A few years ago I had to have one of these 2 lines dug up and spliced since I hit one of them with the rototiller blades. Everything was working fine before the problem in the small work box and I find it odd one leg is now dead.
What should I be checking at this point ? I moved wires around so that I have outside lighting, door openers, lighting downstairs and heat.

 

[pattenp]

First off what you are saying is hard to follow. I assume the main panel that you are describing is a subpanel in the garage that is fed from the main panel in the house. And you are saying that one leg of the power from the house to the subpanel in the garage is now dead. Is this correct? Did you have to reset the breaker in the house panel for the feed to the garage? On a side note if you struck the feeder wire with a tiller then that wire is buried way to shallow. Back on subject… you may have a bad breaker in the house panel for the feed to the garage. Check for power at the breaker in the house. If you have power on both legs at the breaker then you could have a bad feeder wire to the garage.

 

[buzz4041]

Sounds like the breaker in the house is 2 single pole breakers not tied together and only one leg tripped. Go check the feed in the house panel like pattenp said. If they are in fact single pole breakers either tie them together so they work as one or replace with a double pole breaker.

 

[porcupine73]

Does the GFCI now trip/reset properly? I can't quite tell if this is the case, but are the things that are not working now subfed from the GFCI? If possible, the short may have ruined the GFCI when it interrupted the direct hot to ground short. Normally it would not have to interrupt that level of current.

 

[Greatbear]

If the wiring from the main panel to the sub panel is aluminum, there is a chance that one of the legs had opened up because of the surge current. If there was any corrosion building or inadequately tightened lugs, a surge can blow open a marginal connection. Test from the breaker in the main panel to the sub panel. If you lost power in one of the legs, try repositioning and retightening the lugs. If you have power at one end and it's missing at the other, you could have lost a wire underground where it was spliced.

 

[Andamo]

Sorry if I was confusing. Yes, the main panel in the house is a 200 amp with a 100 amp breaker (2 breakers tied together) with the buried aluminum wire going to the garage. I've flipped this breaker of and on quite a few times and nothing has happened. At the sub panel in the garage I only have power to the one leg of the 100 a main breaker. I'm going to pull the cover off the 200 amp box in the house today and see if I have output on both legs.
The odds are that the splice opened up underground. The fellow that did the work was a registered electricial and made the splice inside a plastic box and then filled the box with silicone then wrapped the box with rubber shrink wrap and heated it to seal it further.
The GFCI will still trip and reset and everything ''downstream'' from it still has power.

It just seems strange that the circuit was protected by the GFCI and a 20 amp breaker would open the circuit further back towards the main panel.

 

[pattenp]

The one leg may have been in the process of failing and it was just a coincident that it failed as you were doing your work.

 

[Andamo]

You're probably right. I checked the voltage in the main panel and I have power on both legs so something has happened with the buried cables going to the garage. I've already talked with my electrician and we're going to dig up the wire, make the trench deeper (12'' by code) and put new wiring inside conduit.
Thanks for all the help folks.

 

[Norcal]

You're probably right. I checked the voltage in the main panel and I have power on both legs so something has happened with the buried cables going to the garage. I've already talked with my electrician and we're going to dig up the wire, make the trench deeper (12'' by code) and put new wiring inside conduit.
Thanks for all the help folks.

Try 18" min, or 24" if subject to vehicular traffic, 12" is for 120 volt GFCI protected circuits in residential.

 

[Andamo]

The electrician said that 12'' is code in this area. It runs beside the house and across the yard and there isn't any chance of vehicular traffic.

 

[Norcal]

The electrician said that 12'' is code in this area. It runs beside the house and across the yard and there isn't any chance of vehicular traffic.

Odd code or the "electrician" has not read the NEC.

 

[pattenp]

Odd code or the "electrician" has not read the NEC.

Agree. The basic numbers are: Direct bury 24". In nonmetallic conduit is 18", and in rigid conduit is 12". Those numbers change if under concrete or subject to heavy traffic.

 

[Andamo]

In my post #8, I said we're using conduit and I guess I should have mentioned it would be metal. So 12'' should be up to code then.

 

[Norcal]

In my post #8, I said we're using conduit and I guess I should have mentioned it would be metal. So 12'' should be up to code then.

If it's rigid or IMC, it's just fine, EMT is a no-go...

6" w/ rigid, or IMC, is OK in residential as long as not under a driveway.

 

[kngelv]

If it's rigid or IMC, it's just fine, EMT is a no-go...

6" w/ rigid, or IMC, is OK in residential as long as not under a driveway.

Norcal is correct on this. If you have access to a code book, Table 300.5 is where you want to look. When using plastic conduit you need to go at least 18". When I install any conduit I like to go 24". I can't tell you how many times I've seen seen people trying to put in ponds, gardens, sprinklers and even ice rinks hit conduit at 6". I like to plan for most contingencies – just in case.

James

 

[Andamo]

I'll have to see what he says tomorrow when he stops to see what he needs to do. But this time, we'll do it correctly. The electrician I'm using now isn't the same one that put the original line in.
I'm just glad that I was able to do some creative jumping inside the box so I had the outside lights and door openers working. I don't know how it is in your area anymore, but crimes like theft and breaking and entering are getting worse in my area and I'm at least hoping the lights around the perimeter of the garage are a deterrent.

 

[Falcon67]

You can go 12" on non-metallic under the yard IF you cover it with 2" of concrete. According to my NEC translation book LOL.