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| Subject - isolating grounds | |
| bigvic | I am moving my meter base to my unattached garage and am installing a 400 amp service in the garage. 200 amp 30 circuit panel in the garage and a 200 amp disconnect to the house. If the house is not attached to the garage do I need to isolate the ground and neutral in the house. Or do I leave the grounding at the house like it is and just run three new 2/0 copper thhns to the existing panel. |
| iwire | There are some options here but first the most common way. Put you new service at your garage, bond it and ground it as you would with any service. Run a 4 wire feeder to the house keeping the neutral isolated from the grounding conductor. At the house you will need to connect (or leave connected) the grounding electrodes to the equipment grounding conductor. It sounds like you are going to reuse the existing house panel, if that is the case all the grounds and neutrals will need to be separated if they are not all ready and the bonding jumper or bonding screw at this panel needs to be removed. Now there is another option that can only be used if you are 100% sure of this. Part of 250.32(B)(2) quote: If you that is true along with the rest of 250.32(B)(2) you may run a 3 wire feeder from the garage to house leaving the equipment grounding conductor behind and leaving the house panel bonded as it was when it was the service panel. I personally do not like that way, cable TV, Phone, water and gas lines are all potential metallic paths that can cause problems if you go that way. There are times when it is a better method, long distances from a meter pedestal to the building would be one of these. Bob |
| frenchelectrician | ok for this useage i will really suggest to run true 4 wire set up and i am sure most electrican and inspectors will rather run this route anyway because i do see alot of detached garage and alot of the owner do bring the phone wire and gas pipe and water pipe on some case there. i know it do cost a little more for extra grounding wire but in long run it is better for this route. merci, marc |