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kmaz · 14-12-2012, 11:25

Just ran into a tough snag while installing a new Lofrans Tigres windless. The manual calls for 50mm(1/0) into the housing and to the motor. I tried using 2/0 and there is no way to bend it around the motor. Even the 1/0 they call for seems like a big stretch. The cables have to come into the housing, past the two threaded case bolts, and to the top of the motor. Has anyone installed a Tigres? How did you route inside the case?

I have 2/0 from the batts to a bus bar in the anchor locker(35 feet one way). I hate to run that much copper for safety and switch to 1 gauge for the final 3 feet. Am I over engineering this?

Saltyhog · 14-12-2012, 11:38

The resistance of the cable (and therefore its losses) is proportional to the diameter *and* its length. Therefore, a short (as short as possible) pigtail of the smaller gauge cable will not appreciably increase the cable loss. If the manufacturer specifies 1/0 to the motor terminals, then use that and transition to the 2/0 via terminal block in as short a distance as possible. Adding the short pigtail of smaller cable does not negate the loss savings of the larger and much longer attached cable. Hope that answers your question and makes sense. BTW, are you sure that 2/0 is large enough for that long of a run? Remember, the run is the *full* circuit, so the length of one of the longer cables x 2.

kmaz · 14-12-2012, 11:43

Thanks, Saltyhog.

Not concerned about dropping down in size and understand there will be no side effect. However, bending 1/0 through the case seems impossible. Am I correct that 50mm^2 is 1/0?

Cheechako · 14-12-2012, 12:00

Go down one more size yet for the short cable.

**noelex 77** · 14-12-2012, 12:28

I helped fixed one of these or a friend a few months back and I can imagine 50mm2 wire would be very difficult to fit.
The voltage drop over a small length of slightly thinner wire is rarely a problem. You only need a few feet of wire at the most. The join between the different guages is a problem, however. It is in the worst spot, exposed to water.
What are the lengths of the wire run ?
There are also a considerable number of different cables whith the same sized conductors. Some are considerably more flexible with thinner insulation than others. Some of the "welding cables" are very flexible and thin. While not tinned this may be a satisfactory solution.

PEACETIME · 14-12-2012, 12:50

Ran into that very problem on the last install of the same windless. What we did was to run 1/0 wire, three of them if I remember correctly, inside the
motor cover. I had to flatten them between 2 pieces of boards, being careful to not split the covers, hot water helps the covers be soft and workable. They just need a little help to make the 2 bends around the motor to the studs. We then added heat shrink for insurance.
Those wires were run through the deck to the control solenoid and breaker which was as close as possible. We then stepped up to the larger wire which ran to the batteries.
I must say that if time and a machine shop was available I would rather make a spacer plate about 2 inches thick. You could use the gasket for a template.
Hope that helps

kmaz · 14-12-2012, 12:50

Thanks, Noelex. The busbar is up high against the bulkhead on the dry side. All chain on starboard and nylon on port - dry because the nylon will rarely be used). Busbar will be will be covered and sealed.

I went with 2/0 for a 30ish foot run because I had plenty of room, the run is very straight(down the bulwark) and I like to overbuild things. A few bucks today prevents problems down the road. Not concerned at all with running smaller gauge from the bus bar. Just wanted to see what people were realistically able to get into the Tigres.

kmaz · 14-12-2012, 12:51

Very helpful.

PEACETIME · 14-12-2012, 12:57

I don't believe those engineers ever tried to wire one as per their instructions!
Why didn't they put the studs on the bottom instead ? That would make for a very easy install with larger wires. Engineershttp://www.cruisersforum.com/images/smilies/banghead.gif