BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: Phil C on 25 Feb, 2021, 21:30

Title: Alternator wires thickness
Post by: Phil C on 25 Feb, 2021, 21:30
I plan to replace the three wires which come from my alternator. I notice Rupert Ratio says (Vol. 2, p.282) that wiring on unit singles should be 14 strands of 0.3mm (1 sq mm.) I'm guessing that's standard old fashioned wire, rather than modern thin wall stuff. I plan to use the stuff I've already got in the correct colours, which is 28/0.3 (2 sq mm) thin wall. The o/d of the insulation is almost identical. Is there any reason not to use this?  Thanks for your help as usual.   Phil
Title: Re: Alternator wires thickness
Post by: Phil C on 26 Feb, 2021, 03:54
I should perhaps add that the old, damaged wires I'm taking off are 14/0.3 (1 sq mm.)  Is it okay to replace with 28/0.3 (2 sq mm) thin-wall?  Phil
Title: Re: Alternator wires thickness
Post by: Rog1 on 26 Feb, 2021, 10:02
The only issue I can think of is that you have to avoid stress raisers; where the stiffness of the wire changes suddenly or there are bends which are too tight for the size of wire. There's going to be stress raisers at the join whatever you do, so the join needs to be well supported on each side.
Title: Re: Alternator wires thickness
Post by: Phil C on 26 Feb, 2021, 17:57
Thanks Rog1. I think I've just answered my own question. When the three wires go out of the primary chaincase they then almost immediately turn 90 degrees to go up vertically through another grommet.  The group of three 28/0.3 wires appear to be too thick to want to make that sharp turn. So I guess I'll use old-fashioned 14/0.3 like was on there before.  Phil.
Title: Re: Alternator wires thickness
Post by: Rog1 on 26 Feb, 2021, 23:54
Sounds like a plan. Glad to help.