question Slave cable polarity

[robin craig]

Gents and Gals,

 

I'm making up a slave cable with interchangeable ends with a quick disconnect. The purpose is to start some British MVs arriving soon (hint, hint). I need to be able to use spring loaded clips onto a civvy 24v vehicle or pack and also slave the two between each other once off the vessel.

 

My need is to know which of the inner or outer connections in the head shown below is the positive and which is negative so my new connections are right.

 

Im sure there is a simple way to know but my tiny pea brain is somewhat befuddled!

 

Anyone know please?

 

R

[Richard Farrant]

Gents and Gals,

 

I'm making up a slave cable with interchangeable ends with a quick disconnect. The purpose is to start some British MVs arriving soon (hint, hint). I need to be able to use spring loaded clips onto a civvy 24v vehicle or pack and also slave the two between each other once off the vessel.

 

My need is to know which of the inner or outer connections in the head shown below is the positive and which is negative so my new connections are right.

 

Im sure there is a simple way to know but my tiny pea brain is somewhat befuddled!

 

Anyone know please?

 

R

 

 

Obvious really, as the systems are Negative Earth, then the outer part of the socket is Negative, the centre being the live Positive.

[robin craig]

Richard,

 

I dont doubt your reply, as I am in awe of your knowledge, as always.

 

Can you explain how that is so obvious, so I can understand the convention of what you know.

 

R

[Tony B]

Keep the live one as insulated and seperate as possible to prevent acidental shorts.

[Richard Farrant]

Richard,

 

I dont doubt your reply, as I am in awe of your knowledge, as always.

 

Can you explain how that is so obvious, so I can understand the convention of what you know.

 

R

 

Robin,

 

If you look at the socket on the vehicle, with the protection cap removed, the outer sleeve is a contact surface, if this were live it could easily be shorted out, live (+POS) being the internal contact. I would have used these leads many hundreds of times over the years!

 

If in doubt, just do a continuity test with a meter and you will see.

Edited December 12, 2010 by Richard Farrant

[robin craig]

Thanks for the reply Richard, NOW I understand.

 

regards

 

Robin

[andym]

Gents and Gals,

 

I'm making up a slave cable with interchangeable ends with a quick disconnect. The purpose is to start some British MVs arriving soon (hint, hint). I need to be able to use spring loaded clips onto a civvy 24v vehicle or pack and also slave the two between each other once off the vessel.

 

This is presumably relevant to the recent confusing discussion about British AFVs in "Southampton"?

 

Andy

[Tony B]

:-DDon't forget. look at least twice before connecting!