Battery cut off switch in switch panel?

[MarcJ]

Just in the process of making a box to hold a couple of switch panels for the soon to be installed batteries. This is a wee 20ft vivacity so it's all very small scale!

I was going to put the battery cut off switch in the box as well as the switch panels. Just thinking about it though - that means there will be live 12V terminals inside the box even when switched off. Not good if I have to do any running repairs, is it normal to have the cut off switch near the batteries?

Also I'm debating with myself about putting the RCD consumer unit/sockets on the switch panel - I think this should be fine as I won't be going in the panel when hooked up to mains, any reasons why this is a bad idea?

Here's a pic - just having a think before I cut the holes!

Many thanks!

 

[northwind]

I've mounted my cut off switch in the panel, the main fuse is by the battery.

I have one of the removable key ones, it's setup so we have to remove the key when we leave the boat, as the padlock key is on the same ring.

If you are worried you could easily make a cover for the back of the terminals.

 

[prv]

It's conventional to put the cut-off switch near the batteries, although in our old boat I did have an unswitched run to the panel a few feet away. If I'd needed to work on that I'd have taken the terminal off the battery.

Mains stuff should not be in the same enclosure as 12v stuff, because a stray wire could bridge the two systems and bring the 12v stuff (which is not designed to stop you touching live surfaces) to a dangerously high voltage. If you do put the 240v stuff in that area, have it inside a proper enclosure that covers it on all six sides including inside your box.

Pete

 

[MarcJ]

Thanks both! The cut off switch is the key type, great idea to put the boat padlock key on the same keyring.

Now you mention taking the terminal off the battery, Pete, that's the reason I don't want it in the panel as the batteries are going to be in a not very accessible place, ie under the cockpit area, via the space under the companion way. It's the only logical place I could think of with out spliting them up, as I want their weight distributed evenly.

Take your point about the 240V stuff - the box I have is self contained and think I'll put it somewhere else.

Thanks!

 

[VicS]

I agree with Pete.

Isolating switches normally and best close to the batteries.

Also keep 12volt and 240volt systems quite separate.

If you are installing shore power you might like to read the International standard ISO 13297 http://www.google.co.uk/url?sa=t&rc...cFj3OGIImUfs4HQejcOtmUg&bvm=bv.47380653,d.d2k
If the link works.

It's the only logical place I could think of with out spliting them up, as I want their weight distributed evenly.

You have a lot of battery power then for a "wee 20ft Vivacity"

 

[MarcJ]

You have a lot of battery power then for a "wee 20ft Vivacity"

Yes my brother managed to get two 6 volt 175AH batteries from work - they're 35kg each! once they're in they won't be moved for some time!

 

[David2452]

No problem with the battery management switches, the closer to the batteries the better, also consider an MRBF direct to the battery bank which means every mm of cable is fused.
Under no circumstances put any low voltage AC close to ultra low voltage DC, even running the cables alongside one another is not on unless the low voltage AC is encased in conduit. Any other course would put the install outside of BS EN ISO 13297:2012 Small craft, AC current installations (the link given earlier is now 12 years out of date and not even the BS ISO one BTW) and whilst I realise this is a non pro install that's no reason not to follow the rules, the current ones that is.

 

[VicS]

No problem with the battery management switches, the closer to the batteries the better, also consider an MRBF direct to the battery bank which means every mm of cable is fused.
Under no circumstances put any low voltage AC close to ultra low voltage DC, even running the cables alongside one another is not on unless the low voltage AC is encased in conduit. Any other course would put the install outside of BS EN ISO 13297:2012 Small craft, AC current installations (the link given earlier is now 12 years out of date and not even the BS ISO one BTW) and whilst I realise this is a non pro install that's no reason not to follow the rules, the current ones that is.

Not 12 years out date , only 1 year. Until last year it was current !

However, how about a link to the new version.


Perhaps you should explain in layman's terms what you mean by "low voltage AC" and "ultra low voltage DC"

AC voltages of less than 50?, 25?, 10? ???
and DC of only a few mV ?

 

[David2452]

However, how about a link to the new version.
Perhaps you should explain in layman's terms what you mean by "low voltage AC" and "ultra low voltage DC"

AC voltages of less than 50?, 25?, 10? ???
and DC of only a few mV ?

12 years, 1200 years or 1200 minutes, its not current and not eved BS ISO, No link to the current version is available, it's copyright and not public domain, you can buy it at a discount if a member or pay through the nose if not

AC low voltage is < 1000v AC (1500v for ripple free), ultra low voltage DC is generally accepted as < 120v DC according to BS 7161 for land based, though for marine aplications and NMEA0400 standard <50v DC is the accepted standard.

 

[VicS]

No link to the current version is available, it's copyright and not public domain,

Fat lot of good producing these standards if they are not freely available.

 

[David2452]

Fat lot of good producing these standards if they are not freely available.

The only people that have to adhere are pro's that do have access, and have to pay subscription for the maitainance, they also assume (understandably given their target) a reasonable degree of experience and qualification. Whilst there are many non pro's who would correctly interpret them there are at least an equal number that would not and could misinterpret. All these bodies have to be paid for the job so it aint free

 

[William_H]

Yes my brother managed to get two 6 volt 175AH batteries from work - they're 35kg each! once they're in they won't be moved for some time!

I don't know your Vivacity but with my 21fter I am always trying to get weight forward. It definitely drags its stern with 4 crew in the cockpit. Perhaps you are going to sail single handed in which case 70kg under the cockpit would be OK. If it were me however I would be mounting the batteries mid ships or even under the forward berth. Bear in mind they won't last for ever and you will probably end up fitting a smaller battery later. good luck olewill

 

[MarcJ]

I don't know your Vivacity but with my 21fter I am always trying to get weight forward. It definitely drags its stern with 4 crew in the cockpit. Perhaps you are going to sail single handed in which case 70kg under the cockpit would be OK. If it were me however I would be mounting the batteries mid ships or even under the forward berth. Bear in mind they won't last for ever and you will probably end up fitting a smaller battery later. good luck olewill

Good point(s) Olewill, I'll have to see how it sails afterwards, 99% of the time there will be just 2 of us in the cockpit..