Best 12 pin trailer plug

If you are trying to pass more than a few amps ie brake current or lights only current through the plug it will fail. Most others will too.
For any heavier current, use Anderson plugs, two separate ones if needed, for the fridge and battery supply.

It is fairly useless to try and run a fridge through a trailer plug, same for battery charge current which can initially be quite high amp flow.
Both the fridge and the battery require heavy wire to reduce voltage drop VD to a minimum for best performance and no fry ups of equipment.

Hi Marty, Sometimes you can widen the pins with a small knife or s/driver, they make better contact, cleaning also helps. these plugs should only used for trailer lights,Ross is spot on with battery & frig wiring

I have found Narva products to be of reasonable quality. There is a selection of flat plugs in this link. I am using this socket on my D40 link.

You will note that the smal pins are rated at 15 A and the larger ones at 35 A. I have had my 25 A DC to DC charger running through pin 8 and the fridge running through pin 9 without any problem.

I would steer clear of the stuff BFC are flogging.

Marty mate, in my opinion the flat trailer plugs, both 7 pin and 12 pin are fundamentally flawed in many ways.

The way the contacts are designed
the way the contacts are mounted in the plug
the way wires are connected into the contacts including how poorly the screws are fitted to the contacts
and I could go on
There are just a cheap and nasty design from start to finish.

There is very little any manufacturer could do to improve the plastic rectangular trailer plug....they are just junk.

They simply do not compare to the proven utilux style 7 pin round, of which there are several competently made items on the market.

The second flawed notion is carrying electrical supply in the same plug used to carry mandatory lighting.

There requirements of the two are just so different...the current demands of stop, indicator and brake lights are quite modest and the wire sizes are in general relativly small.

Where as the demands of electrical supply for caravans and the like are at least five to ten times greater and if they are to travel the distances require very much heavier cables
typical ( old incandessant) brake light circuit is 3.5 amps.....typical 3 way fridge is 15 amps.
If you want to charge a battery you need to be starting arround 20 amps and 50 is not unreasonable.

You are far better off with a utilux style 7 pin round trailer plug for your lights & brakes and an anderson or something else as your electrical supply.

cheers