When it comes to electrical systems aboard boats, Arild Jensen knows his stuff. Here's where to ask the simplest or most complex questions about marine electrics.


Postby Carolina » Wed Oct 20, 2010 9:13 am

Will be installing new windlass. 1200 watt with a total length to battery and helm of about 17 feet. If this is enough info can you tell me the size of wire to use? Draw in amps is 80-110. Also, the size breaker you recommend. Thanks
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Re: Windlass

Postby elnav » Wed Oct 20, 2010 1:37 pm

#6 Ga wire will carry the maximum current but at 110amps will incur a 12% voltage loss. #4 Ga wild be better.
Since the manufacturer stipulates 110 Amp as the maximum current a 125A thermal breaker such as the Bussman series 187 sold by Blue Seas is close enough to the 120A rating of the #6 Ga wire.
If you chose to install the #4 Ga wire you could go to a 150 amp breaker to protect the winch motor against a locked rotor condition if the anchor stices or the chain jams. 125A breakers will trip sooner but may incur nuisance trips if the anchor sticks often. However if you decide to use #6 Ga wire you must use the 125A breaker or risk smoking the wire under sever loading, not to mention which a sharp surveyor may reject it.
Arild Jensen
Custom electrical design for cruising boats
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