Deck fitting-large and small diameter pin polarity convention.

[DavidJ]

I’m fitting a 2 pin deck fitting for power to blow up my tender. The fitting has one diameter pin larger than the other.
I assume there must be a convention for which pin is the positive. I’d quite like to follow a convention if there is one.
Any thoughts?

 

[MapisM]

Is it possibly the thing below that you are going to install?
If so, I was once told that conventionally positive goes on the larger pin, but I struggled to understand why that should matter.
I mean, as long as you are only going to use only one plug with its own socket, the different diameters are only important for avoiding connecting the plug the other way round, I reckon.

Oh, and if as I understand you are going to fit the socket externally, you'd better keep it greased.
I installed the same thing on one of my old lake boats, and even if it was inside the cabin and never went anywhere near salt water, it still managed to rust after one season... :ambivalence:

 

[DavidJ]

Is it possibly the thing below that you are going to install?
If so, I was once told that conventionally positive goes on the larger pin, but I struggled to understand why that should matter.
I mean, as long as you are only going to use only one plug with its own socket, the different diameters are only important for avoiding connecting the plug the other way round, I reckon.

Oh, and if as I understand you are going to fit the socket externally, you'd better keep it greased.
I installed the same thing on one of my old lake boats, and even if it was inside the cabin and never went anywhere near salt water, it still managed to rust after one season... :ambivalence:

That's exactly the one and I will go with the positive on the large pin. I agree it doesn't matter in my case because only one application but nice to follow a convention if there is one. The socket is going inside a deck locker but even so I will grease it up as you recommend
Thanks for your reply

 

[jfm]

David I think the answer is that there is no convention on this.

 

[Plum]

I’m fitting a 2 pin deck fitting for power to blow up my tender. The fitting has one diameter pin larger than the other.
I assume there must be a convention for which pin is the positive. I’d quite like to follow a convention if there is one.
Any thoughts?

The 12v pump I use to inflate my tender has a current rating of 25A max. Is the fitting you propose capable? I use Anderson connectors (mounted inside a locker) rated at 50A, marked + and -. I use the same socket to plug in a fuel transfer pump and one day it will also be used to plug in the electric outboard charger. They are not waterproof but have excellent corrosion resistance and will still work when wet.

Www.solocoastalsailing.co.uk

 

[DavidJ]

The 12v pump I use to inflate my tender has a current rating of 25A max. Is the fitting you propose capable? I use Anderson connectors (mounted inside a locker) rated at 50A, marked + and -. I use the same socket to plug in a fuel transfer pump and one day it will also be used to plug in the electric outboard charger. They are not waterproof but have excellent corrosion resistance and will still work when wet.

Www.solocoastalsailing.co.uk

Hi Plum
I guess I have the same 25A pump as you.
At the moment I am using an extension cable with a connector with smaller pins and it works ok probably because its only in use for a few minutes while pumping up the tender so I'm comfortable with the 20A rated connector above.
I love the Anderson stuff and have some 50A connectors but they do look extremely beefy when set against the 25A cable I'm using.
Thanks for your posting as it's made me think and realise that I'm working in the safety margin zone although I do have to look at the crock clips that the pump came with and what I've got is a vast improvement on that.

 

[Assassin]

David I think the answer is that there is no convention on this.

I would agree, just people using a common method and it becoming accepted practice.

 

[colhel]

Hi Plum
I guess I have the same 25A pump as you.
At the moment I am using an extension cable with a connector with smaller pins and it works ok probably because its only in use for a few minutes while pumping up the tender so I'm comfortable with the 20A rated connector above.
I love the Anderson stuff and have some 50A connectors but they do look extremely beefy when set against the 25A cable I'm using.
Thanks for your posting as it's made me think and realise that I'm working in the safety margin zone although I do have to look at the crock clips that the pump came with and what I've got is a vast improvement on that.

You'll most likely have a better set up than me as i couldn't get the high speed pump to work properly with extensions and plugs so in the end i bought a 12v battery (corsa size with a handle) which has lasted without charging since April and my dinghy has more leaks than something really leaky. Been used for other stuff too.

 

[BruceK]

Although there is no convention on this particular plug a common standard on DC plugs is neutral is always the larger blade.