Positive or negative earth

[Hentzant]

DThe I am in the process of completely rebuilding my 1934 rp saloon.As the car has to be rewired what are the pros and cons of wiring negative or positive earth.

[Chris KC]

I'll stick my neck out a bit and say that the difference is largely theoretical, I've used both over the years without issues. Do make sure your dynamo and coil are set up with the corresponding polarity. Ideally run your wiring directly back to the battery rather than earthing through the body, and use the thickest wire you can in order to minimise voltage losses.

[Nick Salmon]

Have a read of this and all will be made clear.
http://www.rrec-northeast.co.uk/positive_negative.pdf

[Hentzant]

Have a read of this and all will be made clear.
http://www.rrec-northeast.co.uk/positive_negative.pdf

Thank you nick After reading this i’ll Stick to the original positive earth system used on the car.

[Stuart Joseph]

Good afternoon. were RP's positive earth?
I have always believed that positive earth wasn't introduced until 1936.

Regards from the creative county - Staffordshire

Stuart

[Hentzant]

Good afternoon. were RP's positive earth?
I have always believed that positive earth wasn't introduced until 1936.

Regards from the creative county - Staffordshire

Stuart

Hi Stuart Well the car was in pieces when I bought it and there was a short battery lead to the chassis with a positive symbol on the connecter.Of course this doesn’t mean it was original to the car.Someone in the past has fitted a later 3 bearing engine so maybe the car was negative earth originally.
Ken

[David Cochrane]

The List of Production Changes shows: Negative earth up to December 1935. My 1933 RP is negative earth.

David

[DaveT]

The List of Production Changes shows: Negative earth up to December 1935. My 1933 RP is negative earth.

David

Hi, my MK1 Ruby was registered on the 10th July 1935 and the numbers correspond to manufacture in April 1935 as she has all her original matching parts and it's wired as positive earth.  

[John Mason]

My March 1935 Ruby is negative earth.

John Mason

[Andy Bennett]

My March 1935 Ruby is negative earth.

John Mason

my 33 RP is positive earth

Andy B