two seperate sub panels run to house, common grnd?

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twistin214

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advice please. 400 amps run to residential garage. 200's parallel feeding to separate disconnects. one 200 was dedicated for house. (ran 4 wire)the other 200 feeds garage and into transfer switch for auto generator. so the generator panel also feeds a 80 amp sub panel to the house.(3 wire). i wanted 4 wire on both and keep everything separate but only got one. i also wanted to land one grnd rod for each. i'm getting confused on where to bond separate feeds? thanks and phone was run also from garage to house. pvc water feeds.
 
Since you're telephone line is not bonded to the grounding system in either building it is not a concern. Is the emergency panel in the house supplied via a transfer switch or does it always take it's power from the feeder from the garage?
 
hornetd, one 200 amp main dissconnect feeds through a panel then into transfer switch/generac generator and into 100 amp sub (gen)panel that is a few circuts in garage. then it goes to house to feed 80amp(gen) panel. second 200 amp main dissconnect in garage also feeds into house for the majority of the circuts. am i right by bonding the two panels together through 2 ground rods and into only one from metallic piping?. thanks for your help. :roll:
 
From your explanation, it sounds like you have two buildings on the same property. It also sounds like one service disconnect supplies building # 1, and the other service disconnect supplies building # 2. Then you have conductors from building # 1 generator supplying building # 2.

Something here does not seem right.... I will have to "noddle" this and draw myself a picture to see if this is compliant.

The phone system is required to be grounded at the POE, and the phone system grounding is required to be bonded to the building electrical system.
 
Pierre C Belarge said:
From your explanation, it sounds like you have two buildings on the same property. It also sounds like one service disconnect supplies building # 1, and the other service disconnect supplies building # 2. Then you have conductors from building # 1 generator supplying building # 2.

Something here does not seem right.... I will have to "noddle" this and draw myself a picture to see if this is compliant.

The phone system is required to be grounded at the POE, and the phone system grounding is required to be bonded to the building electrical system.
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While it is true that the telephone protectors have to be grounded to each buildings grounding electrode system that is not the same thing as having a metallic water pipe between the two that is bonded to both buildings main bonding jumper. The grounding of the telephone protectors does not provide a parallel path for the neutral current since those protectors only conduct under over voltage conditions. The emergency panel feeder from the garage to the house is a problem however because it is three wire. The emergency feeders building disconnecting means will be bonded to the same grounding electrode system as the houses regular feeder building disconnecting means. If the emergency feeder had been four wire then all would be well because only the two feeders equipment grounding conductors would be in parallel. As it is however with the regular feeder's Equipment Grounding Conductor bonded to the same electrodes at each end it will serve as a sneak current path for the emergency feeders Neutral current. When two feeders serve one building then both should have a separate Equipment Grounding Conductor run with the current carrying conductors. Since EGCs do not carry current under normal operating conditions having EGCs bonded at both ends does no harm.
 
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