7 point plugs burnt out

Submitted: Monday, Apr 30, 2012 at 19:59
ThreadID: 95270 Views:2256 Replies:5 FollowUps:4
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Hello everyone. An auto electrician advised today that 7 point plugs are prone to burning out when current is being transferred from the vehicle to a deep cycle battery and fridge in the van. A separate heavy duty cable is recommended between the vehicle and the Van Battery to overcome this problem. My question is this: Has anyone experienced this problem and what damage can be done apart from having to replace the 7 point plugs? I find it outrages, and maybe even dangerous, that caravan outlets can install deep cycle batteries, connect them to 7 point plugs and standard wiring on the vehicle and make no mention of the plugs not being suitable. Thanks JOHN
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Reply By: Member - Toyocrusa (NSW) - Monday, Apr 30, 2012 at 20:45

Monday, Apr 30, 2012 at 20:45
Hi John. Not sure where you have found the instance of a manufacturer wiring up the way you describe, especially to run a three way fridge. Most have the fridge and battery charge wires through an Anderson plug or through the heavier pins in a 12 pin plug. I have them through the 12 pin without a drama now for around three years. Cheers,Bob.

AnswerID: 484668

Follow Up By: Member - Jason B (NSW) - Monday, Apr 30, 2012 at 21:05

Monday, Apr 30, 2012 at 21:05
Mine are also wire up from the factory through and anderson plug. I had to have the vehicle wired to suit.


FollowupID: 759921

Follow Up By: Erad - Monday, Apr 30, 2012 at 21:53

Monday, Apr 30, 2012 at 21:53
The 7 pin plugs (the flat ones anyway) could have a problem because of the design on the pins. They are solid brass with a fine sawcut up the middle. After a few years or many insertins and withdrawals, the pins tend to lose their inbuilt springiness, and they make lousy contact. I always check that the lights on the caravan are all working after I connect up, and often they are not, so I get a penknife out and prise the sawcut open a bit so that the pin makes better contact with the socket. If you are passing a high current through a lousy connection, you will get heat buildup and the pin or socket could readily burn out as a result.

To minimise the risk of this happening, regularly check the splits in the pins and if you see them closing up, carefully open them out so that they make good contact.
FollowupID: 759932

Reply By: Member - bbuzz (NSW) - Monday, Apr 30, 2012 at 21:55

Monday, Apr 30, 2012 at 21:55
My 2006 Windsor was wired uo through the black 7 pin plug and my mate just bought a 2010 Paramount with the same wiring.

We both had to change over to an Anderson plug.

My mate had to insist to the caravan dealer that the 7 pin wouldn't work and get him to re-wire.

The dealer thought I was lying when I told him my plug melted.

They are out there.

Bill B

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AnswerID: 484673

Follow Up By: johno59 - Monday, Apr 30, 2012 at 22:21

Monday, Apr 30, 2012 at 22:21
Thanks guys for the advice. You see them everywhere!!! I have found dealers on lots of issues have very limited knowledge. They just seem to want to take your cash and hope you return to spend your money on their overpriced parts ! Jaycos replacement parts and repairs must be a massive income earner!! johno
FollowupID: 759937

Reply By: The Bantam - Monday, Apr 30, 2012 at 22:57

Monday, Apr 30, 2012 at 22:57
If the electrical load and the battery size in the van is small a standard trailer plug should be adequate....

But the syetem and wiring needs to be correctly designed to limit the current to arrouns 10 amps.

the pins in trailer plugs are good for arround 15 amps.

Personally I do not like the plastic flat trailer plugs, they are simply not as well a desiged item as the traditional round plugs

If you have large batteries or you have heavy drain items in the trailer a standard trailer plug most certainly will not be adequate.

A fridge is a heavy drain item

Mostly 50 amp anderson plugs are used for the connection

AnswerID: 484676

Reply By: Ray - Tuesday, May 01, 2012 at 10:07

Tuesday, May 01, 2012 at 10:07
You will find that most caravan manufacturers do no have much idea how to wire up 12 volt or rather auxiliary power to a caravan.
AnswerID: 484694

Reply By: olcoolone - Tuesday, May 01, 2012 at 10:44

Tuesday, May 01, 2012 at 10:44
We don't see any real issues with 7 pin trailer plugs in general BUT if they are used above their recommended current rating then there could be a problem.

We see a lot of new and used caravans and campers that have below standard shonky wiring and components, the main cause of this is most use unskilled so called trades people to do their work and in most cases they use the cheapest components around.

7 pin flat plugs and socket have a 15amp max rating and the standard round ones have a 30amp max rating per circuit...... They say they can handle this current constantly but I would take it with a pinch of salt and say it should be peak current.

Anything with deep cycle batteries should have a minimum of 6B&S cable through a suitably rated plug and socket that can handle at least 25% more current then needed.

Most installations we will use a3B&S cable and a 175amp Anderson style plug and socket

This is one of the ideal reasons for using a DC-DC charger the charge aux batteries in a caravan or camper..... you have a greater chance of knowing you maximum current load and with a DC-DC charger as it will limit the amount of current to the batteries.

For example if you have a 3 way fridge that most caravans have, they will draw on average 20amps constant, throw in a battery or two and you have another 20 to 30amps plus.... this nearly exceeds 50amp Anderson style plugs and sockets and well exceeds nearly all trailer plugs and sockets by a long shot.

AnswerID: 484697

Follow Up By: Member - Bucky - Wednesday, May 02, 2012 at 06:32

Wednesday, May 02, 2012 at 06:32
Too True coolone !
FollowupID: 760048

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