Isolator switch in the battery box

[Monkeybox]

Hi,

 

I am installing a system from scratch and am wiring my main batteries to the fuse box.

 

As the battery box, which is from a forklift so made of half inch thick solid plasic, extends about 3 inches above the battery, I was planning to install the main isolator switch directly into the box. By that I mean just drill a 20mm hole in the side and poke the switch through.

 

However. As I have come to do this job it has occured to me that this may be a bad idea as the contacts are inside the box at the top where the explosive gas will be. This might be considered a big no no.

 

I have had a boat before with the switch mounted like that in a metal box and there was not a problem for the safety cert.

 

I will be covering the box with a plywood lid which will have vent holes on top.

 

Looking at the switch (the usual big red key one) the contacts are covered but is that adequate?

 

Can't find reference to it in the BSS and have had a search on here but am still not sure.

 

Thanks

[aread2]

Hi,

 

I am installing a system from scratch and am wiring my main batteries to the fuse box.

 

As the battery box, which is from a forklift so made of half inch thick solid plasic, extends about 3 inches above the battery, I was planning to install the main isolator switch directly into the box. By that I mean just drill a 20mm hole in the side and poke the switch through.

 

However. As I have come to do this job it has occured to me that this may be a bad idea as the contacts are inside the box at the top where the explosive gas will be. This might be considered a big no no.

 

I have had a boat before with the switch mounted like that in a metal box and there was not a problem for the safety cert.

 

I will be covering the box with a plywood lid which will have vent holes on top.

 

Looking at the switch (the usual big red key one) the contacts are covered but is that adequate?

 

Can't find reference to it in the BSS and have had a search on here but am still not sure.

 

Thanks

It's how ours is set up. The switch is mounted at the top of the battery box on the side. Not a problem if the ventilation is up scratch. In the BSS guide there appears to be no stipulation as to the location of the circuit breaker except that it must be as close to the battery as possible and ignition protected if it is in gas or petrol compartments.

[Monkeybox]

Oh good. I was worried I might get a diatribe about being a liability to myself.

That gives me confidence to proceed.

The alternative is to make a seperate little box to the side for the switch which I think will look unneseccary, not to mention be more work!

 

Ta.

[RobinJ]

I am installing a system from scratch and am wiring my main batteries to the fuse box.

 

As the battery box, which is from a forklift so made of half inch thick solid plasic, extends about 3 inches above the battery, I was planning to install the main isolator switch directly into the box. By that I mean just drill a 20mm hole in the side and poke the switch through.

 

However. As I have come to do this job it has occured to me that this may be a bad idea as the contacts are inside the box at the top where the explosive gas will be. This might be considered a big no no.

 

I have had a boat before with the switch mounted like that in a metal box and there was not a problem for the safety cert.

 

I will be covering the box with a plywood lid which will have vent holes on top.

 

Looking at the switch (the usual big red key one) the contacts are covered but is that adequate?

 

Can't find reference to it in the BSS and have had a search on here but am still not sure.

We were hammered by the first BSC, one of the points was no ventilation in the top of the battery box! Despite my claims that dropping a spanner through the holes was far more dangerous than the lid blowing off, we had to comply, so if its vented, don't see a problem.

If you are starting from scratch, why not fit proper isolator switchss instead of the cheaper red plastic ones?

Provided you install it in the centre away from the temrinals, I cannot see any major problems!

[paulcatchpole]

I can't find anything in the BSS that would stop you putting the isolators in with the batteries, there's the following (main) advice, plus other related items in the section...

 

 

Buuuuuuuuut...

 

I wouldn't, personally, for the reason the OP has already thought about, that you've got sodding great contacts, likely to be operated under load, in a space with a quantity of hydrogen gas.

 

PC

[blackrose]

I can't find anything in the BSS that would stop you putting the isolators in with the batteries, there's the following (main) advice, plus other related items in the section...

 

Buuuuuuuuut...

 

I wouldn't, personally, for the reason the OP has already thought about, that you've got sodding great contacts, likely to be operated under load, in a space with a quantity of hydrogen gas.

 

PC

 

I tend to agree. The contacts of my isolators are inside the box and I'd never really thought about it before. Had I read the OP's question and been making the box and installing the isolators myself, I think I'd have them outside.

 

Some of the good quality ones come in their own boxes and can be surface mounted. http://www.power-store.com/?id=190

 

The other question is the quality of the isolators themselves. Someone with more knowledge will probably be here soon, but I was told that the contacts of cheap isolators can fuse together over time, meaning the batteries might not be isolated when you think they are.

Edited August 19, 2010 by blackrose

[WotEver]

The other question is the quality of the isolators themselves. Someone with more knowledge will probably be here soon, but I was told that the contacts of cheap isolators can fuse together over time, meaning the batteries might not be isolated when you think they are.

They can also make really poor contact, as I found out a few years back when my engine wouldn't start. It took me ages to realise the battery wasn't actually flat.

 

Tony