I plan on running power from my free standing meter pedestal to a new garage. It will be 100 amp service. This meter powers my house also. It is a 200 amp meter. There is room for another breaker in the meter. It will be a shorter and easier run by doing this and that was suggested when I buildt my house 21 years ago. My question is do I have to run an equipment ground conductor with the two hots and a neutral since, I don't believe it will be a sub panel if it comes off my meter pedestal. Second, my service panel on the house is 200 amp with 4/0 al. I planned on changing that breaker to 100 amp in the house. My run to the garage is a total of 130 feet, 3-#3 cu conductors and #ground. Not sure about the ground, run in 2" pvc conduit. Any suggestions?
Power from free standing meter pedastal
- Thread starter Breezy
- Start date
Stuart in MN
Well-known member
From your description, it sounds like the meter pedestal is the main disconnect point for the property. That means both the house and the new garage are both considered subpanels, so there should be separate neutral and ground wires running to the house as well as to the new garage.
I'm not sure why you would want to reduce the breaker size for the house from 200 amps to 100 amps.
I'm not sure why you would want to reduce the breaker size for the house from 200 amps to 100 amps.
joe_padavano
Well-known member
^^^This!
In most rural areas, this is often called a "farm panel", as the main disconnect at the remote meter feeds the house and the barn on separate breakers. A four-wire run is required from the breaker or disconnect at the meter panel to each sub-panel.
When I did my elec, at the recommendation of the power company I popped the cover off the meter base and there were a spare set of lugs which I used to run to my 200 amp panel in the shop. My meter is on the final pole in the yard.
Doing it that way the shop panel is not a sub, so only 3 wires and at that time only 1 ground rod.
Doing it that way the shop panel is not a sub, so only 3 wires and at that time only 1 ground rod.
wyliesdiesels
Well-known member
As has been said, 4-wire is required after the first disconnect. So yes an EGC is required.
Why are u changing your house disconnect from 200a to 100a? Have u done a load calc?
If u do end up having a dual lug meter pedestal, then u can do 3-wire. But i dont recommend that as u wont have overcurrent or fault protection. I wouldnt want that much non-fused wire on my property.
Why are u changing your house disconnect from 200a to 100a? Have u done a load calc?
If u do end up having a dual lug meter pedestal, then u can do 3-wire. But i dont recommend that as u wont have overcurrent or fault protection. I wouldnt want that much non-fused wire on my property.
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As far as changing the breaker in the house to 100 amps, I thought it would be the best thing to do since I'm running a 100 amp service out to my garage. The meter pedestal is rated for 200 amps. Didn't think that I should have two main breakers off my pedestal combined to be 300 amps. I'm quite sure that 100 amps would be sufficient for my house since I don't run anything big, like welders or a/c. It is a meter pedestal that will have two breakers supplying my house and garage. Right now my house doesn't have an isolated neutral. The neutral is bonded to ground. Been like that for 21 years. Just wondering if I can wire my new garage up the same way.
Speedy Petey
Well-known member
Well, the OP's setup is different. As he states, he is coming from a breaker, so he MUST run a 4-wire feeder.
And two ground rods are typically required, unless you want to buy the $800 tester to test for 25ohms.
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Speedy Petey
Well-known member
21 years ago it was allowable to run a 3-wire feeder from something like a pedestal, even from a main breaker. There were conditions to be met but right now that's irrelevant. This exception for a 3-wire feeder was removed from the code quite a while ago so the folks telling you that you need to run 4-wires to your garage are correct.
The fact that you will have two main breakers, and that they will total more than 200A is not an issue at all. For something like your residential shop it is highly unlikely that you will ever draw anywhere near 100A, and the same goes for your house. The thought is that it is extremely unlikely that both buildings will draw near their maximum at any time and/or at the same time.
theoldwizard1
Well-known member
So if the original installation to the house was 3 wire, does it have to be upgrade to 4 wire when the new service to the garage is installed ?
Some meter bases do NOT have a disconnect (fuse/breaker), but do have double main lugs (or the POCO allows double main lug adapters to be installed). In this case, each building must have its own ground rod(s).
Thanks for the info guys. So what I'm getting out of this is that if I run 4 wires to my new garage with an isolated neutral in my subpanel with two ground rods and leave the service to my house the way it is, I should be alright? We don't have any inspections out here as long as the building is detracted from the house.
Speedy Petey
Well-known member
Certainly not. Codes are not retroactive.
Most meter pans do not have double lugs. Some are available with them or will accept them. IMO they are by far the exception rather than the rule.
No matter what, a detached structure served by a feeder must have at least one grounding electrode of some sort. If a rod is installed the resistance must be proved or a second rod installed.
theoldwizard1
Well-known member
Generally, you are correct.
However, the loophole is, if the inspector decides the changes/upgrades are "sufficient" they can demand that you upgrade the entire system.
wyliesdiesels
Well-known member
The OP isnt doing anything with his house feeder so its not required to be changed or brought up to current code.
Speedy Petey
Well-known member
No he can't. Where did you get this myth from? Not unless he has a written code section to back up his interpretation.
For instance, some areas will require smoke detectors installed if a certain area of a home is renovated, or a certain dollar amount project/addition is done. These are things that are a written legal part of some local codes, not the whim of some inspector.
wyliesdiesels
Well-known member
An isolated neutral is reguired so neutral return current doesnt flow on grounded metalic pathways.
The EGC is needed to provide a low impedance pathway for fault current.
Speedy Petey
Well-known member
wyliesdiesels
Well-known member
Perfect.
This should be a tag line to every post about a sub-panel.
No kidding.
Or how about a sticky!
I can think of a few stickys that are needed...
Like the difference between EGCs and grounding electrodes...
Rock knocker
Well-known member
- Joined
- Aug 14, 2014
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Nice response