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Re: Mid point ground return wires
At 05:33 AM 12/20/95 -0500, you wrote:
>Hi Morgan, The new NEC also states that ground fault protection must be
>included on most instalations. Kind of makes mid"point/circuit'' grounding
>difficult.
Mid-point grounding has nothing to do with ground-fault protection ...
Mid-point grounding should be used for the reasons stated here in many
recent posts - it makes for a safer, and less problem prone, install by
'effectively' reducing your high voltage in half. This is on the secondary
side of the transformer.
Ground-fault protection is on the primary side of the transformer and should
be used to protect against current leakage, or short-circuit to ground,
situations as can happen when a primary winding shorts to the core of the
transformer. It also will protect a properly wired circuit in cases of where
water gets inside and there is current flow through the surrounding dampness.
Ground Fault Circuit Interrupters (GFCI) work by monitoring the current flow
in both the 'HOT' wire and the 'NEUTRAL' wire - under normal operating
conditions these will have the same amount of current through them. If more
current flows in the 'HOT' wire than in the 'NEUTRAL' then there is current
leakage to ground somewhere and the GFCI will interrupt the AC supply.