Watermaker Wiring

[Charlie]

I am trying to make a decision on how to wire up my watermaker. Originally the compressor was engine driven. I have converted it to a 125v 3/4 HP motor now. It works fine in the shop but now I need to make it work on the boat. I have a 3.5kw generator which will be the source of power for the watermaker. The watermaker recomends a 30 amp breaker. My AC panel is full. There are no more spaces left. I was thinking of running a sub pannel as is often done in houses. In order to do that I would need to remove one of the Ac breakers and install a 30 amp breaker that would bring power to the sub panel. from there I would run the watermaker as the only AC load and then rewire whatever load was taken off of the main panel. It seems a bit clumsy to me but I can't think of any other way to do it. Doe you guys have any ideas?

[Beausoleil]

One option would be to install the new sub-panel physically somewhere between the main AC panel and some of the AC loads, and move those loads' breakers to the sub-panel. Lots of work, but you'd free up space for future breakers.

Of course, that would only be prudent if you could re-run some of the circuits without pulling new wire for the existing circuits. And if you don't overload your AC system - we can assume you did a sanity check to make sure the 30A load wouldn't overwhelm your AC system - for a 3.5kw genset, you won't be able to run much of anything else simultaneously - like charging the batteries (although you could probably run the genset for the bulk phase, and then startup the watermaker once it's well into absorption?)

[Charlie]

Beau:

In re reading my post I see I wasn't too clear. The Genset has a single 30 amp breaker when in 120v mode. I figure I could only run the watermaker and then would have to charge the batteries once I was done making water. Fortunately the watermaker that the PO installed is of such capacity that I can get a couple of days worth of water in an hour or so.

[Cheechako]

Interesting... my catamaran came with a Northern Lights gen set and 1.5 hp watermaker. I sold the gen set and mounted the watermaker pump on one engine! got rid of about 500 lbs in t hat hull in the process. Rarely had to make water when not motoring already.... I see no problem with a sub panel though.... seems a good way to go.

[Viking Sailor]

Run a circuit from the 30A breaker on the gen-set to another 30A breaker at the watermaker. The breaker on the gen-set will protect the gen-set and the circuit to the watermaker. The breaker at the watermaker will protect/operate the watermaker.

[Charlie]

Thanks Viking that sounds like a good idea.