Earthing a wooden boat. Is it really Black Magic?

[stuhaynes]

I've already posted this in reader to reader and the first advice was to repost it here! The answers are important because I want to minimize the damage to the wood and the propeller etc.

This is a follow on from a previous post. We have three electrical power sources on board, 24v batteries, 1500w inverter power and a 10 amp shore supply.

Is it acceptable, given that our boat is wood, that we earth all three systems via our brass sea cock?

Shore power already has an earth connection back to land but I can't help but wonder about secondary earthing.

Any advice would be much appreciated.

Thanks, Stu

 

[VicS]

I see no reason to earth to a seacock

The shorepower earth, along with the circuit breaker and RCD which you presumably have, will give you the necessary safety protection that you require when using shorepower.

The shorepower earth should be connected to the DC system negative as close a practicable to the battery negative, assuming a negative earth system and also not a totally isolated system, although the relevant international standard, ISO 13297 does permit this connection not to be made provided there is a "whole craft" RCD fitted.
If the connection is made and you leave the shorepower plugged in ( even if not actually in use) a Galvanic isolator in the shorepower earth connection may well be advisable especially if you have any cathodic protection anodes.