Standby generator eart connection?
Standby generator eart connection?
(OP)
Advice required on the connection of a mobile standby generator.
We have a sub station with a LV Earth to which the star point of the supply transformer is connected. The supply to is 415V 3-phase + Neutral. Also connected to the LV earth is the earth bars & metalwork of the LV switchgear. We have a separate earth for the HV switchgear metalwork.
We have a connection point for connecting a standby mobile generator when required, and this connects to our LV board and supplies power by way of a changeover switch. This is interlocked with the mains supply so that only one source can be on at any one time.
Now we have had a visit by some copper thieves and all the earthing has been nicked. I am in the process of installing the earths again, but not quite sure what to do with the generator earth.
I thing I'm right in saying that a standby generator should have its own independant earth, but I am concerned that this will get nicked again. What I'm thinking of doing is running an earth connection from the generator point to the LV earth inside the sub. If I need to connect a generator to supply standby power if mains power is off, then the generator earth would be connected to the LV earth, and I would remove the link connecting the transformer neutral point to the LV earth. Replacing this link and disconnecting the generator when mains is to be restored.
Is this OK?
TIA
We have a sub station with a LV Earth to which the star point of the supply transformer is connected. The supply to is 415V 3-phase + Neutral. Also connected to the LV earth is the earth bars & metalwork of the LV switchgear. We have a separate earth for the HV switchgear metalwork.
We have a connection point for connecting a standby mobile generator when required, and this connects to our LV board and supplies power by way of a changeover switch. This is interlocked with the mains supply so that only one source can be on at any one time.
Now we have had a visit by some copper thieves and all the earthing has been nicked. I am in the process of installing the earths again, but not quite sure what to do with the generator earth.
I thing I'm right in saying that a standby generator should have its own independant earth, but I am concerned that this will get nicked again. What I'm thinking of doing is running an earth connection from the generator point to the LV earth inside the sub. If I need to connect a generator to supply standby power if mains power is off, then the generator earth would be connected to the LV earth, and I would remove the link connecting the transformer neutral point to the LV earth. Replacing this link and disconnecting the generator when mains is to be restored.
Is this OK?
TIA






RE: Standby generator eart connection?
RE: Standby generator eart connection?
RE: Standby generator eart connection?
Regards
Marmite
RE: Standby generator eart connection?
1. Use a grounding conductor to ground the generator frame to the main ground grid.
2. Connect the generator neutral to the system neutral so as to use the existing system ground to ground the generator neutral.
3. A separate ground system for the generator is a code violation in many areas. It may lead to lethal touch and step voltages in the event of a fault.
4. A three pole transfer switch with a solid neutral connection is the simplest, most dependable connection. A four pole transfer switch may be needed for some types of ground fault sensing schemes, but many four pole transfer switches are installed where they are not needed through incomplete understanding of the system.
Bill
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"Why not the best?"
Jimmy Carter
RE: Standby generator eart connection?