My guess would be that your water heater is corroded and on open circuit.quite a common occurrence.

Peter

Peter Forbes
Carango 54035

On 6 Jun 2013, at 13:02, Tony Robinson <tonywrobinson51@...> wrote:

Hi everyone,

When I run my generator, everything works perfectly - all the electrical circuits, especially the water heater, are fine.

When
I connect to shorepower, each time I switch on the water heater, and
ONLY the water heater, I trip the fuse behind the 240 volt switch
panel. It is as if the water heater needs more power than the shore
connection can supply.

I have changed the cable to the
shorepower. I have bypassed the plug and socket in the hull and the trip fuse in the lazarette, by connecting the shore power (with new
cable) directly to the cable after the fuse in the lazarette.
But.....each time I switch on the water heater, the second trip fuse,
behind the 240V panel, trips.

Remember, everything is fine when the the generator is running and supplying 240V.

I
believe there is a bad connection somewhere between the trip switch in
the lazarette and the water heater, but where should I look ? It seems
as if the the water heater draws too much power for the shore power to
supply, but the shore power is rated at 30 amps and everything has
worked fine for the 6 months before, in the same marina (in Sicily). If the water heater were faulty, then I assume it wouldn't work with the generator, yet it does.

I would be grateful for any suggestions.

Regards, Tony Robinson

Catriona R Amel 54 #102
* T