Another subpanel question

[poorboy87]

Hi guys and gals.
Long time listener. First time caller. New guy here with another subpanel question.
My name is Tim and Im an Automotive Technician in southern Indiana. I have a small old farm house that my wife and I bought about 2 years ago. House was built in 1890. On the property is a 1.5 car garage about 70 feet from the house. Its a block building and was put up in 1950.

The house has been updated to 200 Amp service recently. I dont like how it was done and I dont believe its done correctly. The service panel is in the mud room of the house. The service panel is fed from the meter with SER throught the basement and up into the mudroom. The garage has three lights in it and one recepticle on a 20A breaker. That breaker also feeds the an outside recepticle at the house, the one light in the cellar and one recepticle in my sons room.

I am ready to install as sub panel in the garage. After talking to my electric provider I was told the house needs to have main breaker installed below the meter base to serve as a master disconnect.

I have been reading here on GF and asking around and have come up with a plan. I would like to do this correctly and not open up a can of worms with the house electrical as well.

So heres my plan. Tell me if its right or wrong.
I purchased a 200A Siemens outdoor mainlug panel with feed through capabilities. Im going to install it under the meter base outside. The bottom of the panel will feed into the house to supply power. From what Ive read on here I will need a 90A double pole circuit breaker to feed off the main lug and to the garage. My plan was to use 2-2-2-4 MHF off that breaker and to the garage. Im going to run it in conduit the whole way because Im OCD like that. I also bought a Siemens 100A panel for the garage and two ground rods.

My questions are:
1. Do I ground the Main lug at the house?
2. The ground on the MHF needs to be bonded to the panel at the Main
service panel and Ran to a ground bar on the service panel at the garage?
3. How do I run the main feed into the garage? Should it be ran up and over
the eves or knock a hole in the wall and feed it in.

Ive been reading many posts and have and Idea of what needs to be done but would like some clarification.
Thanks in advance
Tim

 

[poorboy87]

Here is where the main lug panel will go. There is a ground rod beneath the panel that the house is grounded to.

This is the service panel for the house. The grounds and the neutrals are on the same bar. From what I have read it shouldn't be this way.

This is the wiring in the garage. Yes that is cloth wrapped wire in there.

This is the main lug panel I bought

This is the service panel I bought

Here is where I was planning on mounting my service panel.


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[Mustang51js]

That breaker outside will be your new main breaker, so you need to extend or rerun the ground wires from water meter and ground rods. You do need to unbond he grounds and nuetral bars in the new sub panel which is your old main panel.

 

[Mustang51js]

You also need to replace the wire going to your old main panel with 200 amp Seu cable since you need the 4 wires now to make it a sub panel.

 

[poorboy87]

Dang. I was hoping to not get into it that much. So will the meter base main breaker and old main panel need to be grounded with ground rods?


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[Mustang51js]

You allready have a ground rod under the meter so all you need to do is come off that and install it into the main breaker. You may need to add another ground rod if your area calls for it,and you would need a ground rod at the garage for that panel. Another option if you don't have a full panel would be to move the panel within 3 feet of the pipe coming into the house. Then you won't need the main breaker outside. You would have to install a splice box and run wires over or make it a small sub panel. The meter itself doesn't need a ground wire,just the two hots and neutral feeding through

 

[Mustang51js]

The panel the way it is with grounds and neutrals would be ok if you didn't have to add the main breaker. The only reason you will have to separate them is because that panel would be a sub panel. Looking at your pics again you could make the location of where your panel is now a 100 amp panel. You would have to see if it's cost efficient to move though panels around. Either way you do it it's going to take some time

 

[poorboy87]

Hmm. Ill do some more searching and price some SEU.

What would it hurt to go ahead and install the main breaker and then run the power to the garage and wait to do switch the house over? There would still be a ground via the ground rod at the old main panel and then I could ground ground the rest of it?

 

[sands35]

That block looks wet? Where you going to mount the panel directly to the block wall?

Put some water block on the block and then a back primed plywood panel?

 

[pattenp]

I'm at a bit of a loss. Why not just come off your existing service panel with the 90A feed to the garage. Why are you adding another panel outside? Also the panels you purchased are both main breaker panels. You referred to one as a main lug. Just seems to me you're doing way more than what's needed.

Edit: The outside disconnect below the meter is not needed unless it's a local requirement. The main breaker in the service panel in the house is the main disconnect.

 

[poorboy87]

I had thought about that. Local code wants a main disconnect within x amount of feet from the meter base. The way it is now it was grandfathered in.

I still might just put a breaker in the main panel and not do the external breaker.


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[pattenp]

If you are grandfathered, adding a sub-panel in the garage fed off of the existing main service panel should not cause you to have to update the service disconnect to be outside. You have plenty of space in the existing panel to add the feed to the garage. Take that outside main breaker panel back and save yourself money and a lot of unnecessary work.

 

[wyliesdiesels]

Agree with PattenP: its grandfathered so they cant make u put a main disconnect in. Just feed off your house panel. Adding a main disconnect outside is a TON of work and not necessary!

 

[poorboy87]

Ok. New plan. If I feed off the existing service panel do I Tie the ground cable and the neutral of the MHF to the neutral bar on the main panel?


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[pattenp]

The wires of the MHF land in the main panel the same as any circuit does. The two blacks/hots go to the double pole breaker, the neutral goes to the neutral/ground bar and the equipment ground goes to the neutral/ground bar. The main panel is the only place that the neutral and ground are bonded together(can land on same bar). The garage sub-panel is where the neutral and ground are isolated/separated. The neutral is not bonded to the panel box. You will need to buy a ground bar kit for the sub-panel.

Edit: You may need to buy a lug for the neutral/ground bar in the main panel for the #2 neutral to fit in. I doubt the #2 will fit in any of the holes of the existing bars.

 

[Mustang51js]

I'm at a bit of a loss. Why not just come off your existing service panel with the 90A feed to the garage. Why are you adding another panel outside? Also the panels you purchased are both main breaker panels. You referred to one as a main lug. Just seems to me you're doing way more than what's needed.

Edit: The outside disconnect below the meter is not needed unless it's a local requirement. The main breaker in the service panel in the house is the main disconnect.

The reason they wanted a main breaker outside is the same around here,anything longer than 3 feet after entering the house the poco wants a main breaker so no unbreakered power is traveling in the house. He said his power goes across the basement so I'm assuming it's a decent distance or they wouldn't want the main breaker under the meter.

 

[Mustang51js]

Agree with PattenP: its grandfathered so they cant make u put a main disconnect in. Just feed off your house panel. Adding a main disconnect outside is a TON of work and not necessary!

You can't say it's grandfathered in when he said service was updated recently which I assume wasn't inspected. If it was and passed then he can argue it a little.

 

[pattenp]

It puzzled me as to why he would be required to add the outside disconnect because of adding a feeder to the garage if his existing service with the disconnect in the main panel was approved at the time of the upgrade.

The reason they wanted a main breaker outside is the same around here,anything longer than 3 feet after entering the house the poco wants a main breaker so no unbreakered power is traveling in the house. He said his power goes across the basement so I'm assuming it's a decent distance or they wouldn't want the main breaker under the meter.

 

[sberry]

When I started to read this thread wondered how long it would take to get to adding a feed from the existing panel, its second best to as good as it gets.

This is the service panel for the house. The grounds and the neutrals are on the same bar. From what I have read it shouldn't be this way.

That is now the service main, it is as it should be.

 

[poorboy87]

We don't have to have it inspected around here. In my case the distance from the meter to the sub panel is 15 feet or so. They want it within 5 feet I think. This is a newer code that they came up with recently.

The original plan was I was wanting to do a full 200A service to the garage so I called the electric company to see what it would involve and what I would need to do. He said it would need the main breaker put in and then disconnects and so on. Money ran out. Fast forward to now I again called the electric company out and we came up with a new plan of only 100A and the master disconnect.

This is all new to me so I was going off of what he said. After having done some research the idea to tap into my main panel and feed out did cross my mind.


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[Mustang51js]

If that's the case then just run off old panel like said above and then you don't need to get involved with the poco at all.

 

[poorboy87]

Sweet. Saves me some money for light fixtures. How would I go about running it into the block building?


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[Mustang51js]

If I was doing it I would run pvc pipe either right to the panel if it's possible or else you have to install a junction box.

 

[theoldwizard1]

MHF must be in conduit anytime it is above ground, including inside of a building. Use Schedule 80 on the sweep (bend) going down into the ground.

For the out building, the simplest thing to do is come up along the side of the building outside the wall you want to mount the your pan box on. Install and LB (a.k.a. "pull box", "pull elbow") and right through the wall into the back f the bow if possible. You may have to go in above the box and install another elbow.



BTW, when it comes to electrical, pattenp, Wylie and sberry are the "go to guys". Wait where was Charles ?

 

[poorboy87]

Thanks guys! Ill post up when I get this project underway. I need to rent a trencher.

Would you guys run conduit the whole way or just bury it?

If I do direct bury it.
Part of the MHF will run under my gravel driveway. Think I should direct bury most of it and then run conduit under the driveway?


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[pattenp]

My preference is to put it in PVC conduit all the way. It's cheap protection.

 

[poorboy87]

What size conduit is best for 2-2-2-4? I found 1.5 inch for about 5 bucks a stick. 10 Foot sticks

How much extra wire do you guys get? I've got roughly 120 foot span to run. I was thinking 5 foot extra.


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[poorboy87]

Upon further reading Ive got another question.

From the breaker box to the barn with all the bends Im looking at roughly 120 Feet.
Is that too much of a run for 2-2-2-4MHF?

 

[pattenp]

1.5" conduit is the smallest I'd use, but I suggest 2". The 120' is not a problem for 90A using -2-2-2-4. Also the total degrees of bends is not to exceed 360 between pull points.

 

[poorboy87]

Thanks!
Pull points meaning access to the cable within the conduit?

 

[Syberia]

Can also be a junction box if you have a need for one at that location.

 

[Mustang51js]

I was always under the assumption that you can't splice in a pulllbox like that

 

[Norcal]

I was always under the assumption that you can't splice in a pulllbox like that

It has to be marked for cubic inches in order to do so, & be of sufficient size to splice in it.

 

[Charles (in GA)]

Be sure and cut off and remove or cut back and disable the existing power to the garage. You are not allowed to have multiple circuits supplying a detached building.

Charles

 

[poorboy87]

Ok will will do.


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[poorboy87]

Starting on it yesterday. So far going ok. Only hit one snag along the way. Found an old barn foundation about 15 feet from my garage. That'll be fun to bust out.

Bummer...

Old cable extraction attempts were futile. Guess I'll dig it up later


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