Fuse Box - fit above weed hatch?

[Richard10002]

I need to fit a 425A fuse near the battery bank, which is at the rear starboard side under the cruiser stern. It's a big fuse, so needs a fairly deep box, (80mm).

 

There's is a U-shaped channel under the lifting part of the deck, the front of which would take a wooden board, to which I would fit an ABS box for the fuse.

 

However, this would mean that the cables and fuse box would be above the weed hatch. They wouldn't interfere with opening it, but there is the vaguest chance they could be disturbed when messing about in/with the hatch.

 

The battery isolators, relay, and a fuse, are in a similar location but at the front end of the cruiser stern under the front lifting part.

 

In my opinion, this is the best place for the fuse and box, about 12" from the +ve battery terminal, easy to access, and doesn't require fixing to the outer hull or the fuel tank wall, ( which would make the box hard to access in any case.

 

Are there any rules as to the route of battery cables, and the positioning of fuses, particularly in the area above the weed hatch? And does the above sound OK?

 

Many Thanks,

 

Richard

Edited May 5, 2012 by Richard10002

[Richard10002]

Just read Part 3 of the BSS Essential Guide.

 

Can't see anything that would prevent me running the cable to a fuse box above the weed hatch. However, the run I am proposing takes the cable above, and pretty close to the engine exhaust. The exhaust is well wrapped, but is an obvious possible source of heat.

 

Should I avoid this route if I can, or is it OK, perhaps with some precautions?

 

Many Thanks,

 

Richard

[RLWP]

My experience of weedhatches is that they generally have heavy, clumsy components which you end up moving in a tricky space with numb hands. I would want to make sure that the electricals were really well protected

 

Richard

[Chris Pink]

If the box is IP65 protected, mechanically protected and the cable shrouded from the exhaust by metal conduit or a heat shield it will be ok.

[Richard10002]

If the box is IP65 protected, mechanically protected and the cable shrouded from the exhaust by metal conduit or a heat shield it will be ok.

 

Thanks Chris..... I'll be drilling some holes in the sides of the box for the cables to pass through, so it's more likely going to be IP55 protected. I suppose I could seal around the wires to make it IP65.

 

What do you mean by mechanically protected?

 

On the heat shield thing.... The exhaust is wrapped in some kind of heat shield. Could I wrap the cable in heat shield, or does it need to be a physical metal barrier, say a centimetre from the exhaust, and about 4 cm from the cable? If a metal conduit, could this just be a tube slid over the cable, and positioned in the vicinity of the exhaust, or does it need to be fixed to the boat, over the cable.

 

Forgive my ignorance ... It's all a bit new to me.

 

Richard

[Chris Pink]

Flexible conduit is pretty cheap and can be fitted to the box maintaing the watertight integrity.

 

Without seeing it it's difficult to tell and any advice could be over the top. I think you should take a view on whether your cable run will get too hot and go with that. The outcomes are the BSS examiner says put in more heat shield or it gets noticeably hot in use and you decide to sheild it. Cables near the exhaust doesn't sound great but as I say, without seeing it...

 

I've re-read your OP and.... Why do you need easy access to a 425a fuse? Are you planning many catastrophic failures? Much better to have it in a difficult place and keep the cable runs sensible. ( where they are now?). I assume they run around the outside of the hull? Keep it there.

[RLWP]

Wow, I bet that a 425A fuse is pretty spectacular when it blows

 

Richard

[Richard10002]

Flexible conduit is pretty cheap and can be fitted to the box maintaing the watertight integrity.

 

Without seeing it it's difficult to tell and any advice could be over the top. I think you should take a view on whether your cable run will get too hot and go with that. The outcomes are the BSS examiner says put in more heat shield or it gets noticeably hot in use and you decide to sheild it. Cables near the exhaust doesn't sound great but as I say, without seeing it...

 

I've re-read your OP and.... Why do you need easy access to a 425a fuse? Are you planning many catastrophic failures? Much better to have it in a difficult place and keep the cable runs sensible. ( where they are now?). I assume they run around the outside of the hull? Keep it there.

 

Appreciate it's hard to comment without seeing it.... One day I'll work out how to post a picture.

 

I don't need easy access to the fuse box, it's just a consequence of what looks like the best route and spot. The existing 25A charger cable is only 25mm2, and it's route is a bit tortuous around the opposite underside of the engine hatch drain channel. The route I'm choosing is shorter, with less bends, which seems much more sensible for 2 x 2.2cm diameter cables.

 

Rather than seeing how it goes with the heat from the exhaust, i'll probably get some of this:

 

http://www.ebay.co.uk/itm/REFLECTIVE-HEAT-SHIELD-SLEEVE-25mm-DIAM-X-1m-/260929145173?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3cc096c955#

 

Richard - the fuse is associated with a Sterling 2500w inverter charger ... Apparently, the inverter is rated to 7200va for very short bursts, which can involve up to 600A in the 12v cables. The fuse takes a few minutes to blow at 1.5 times it's rating, so it won't be going with a bang.

Edited May 6, 2012 by Richard10002

[smileypete]

Rather than seeing how it goes with the heat from the exhaust, i'll probably get some of this:

 

http://www.ebay.co.uk/itm/REFLECTIVE-HEAT-SHIELD-SLEEVE-25mm-DIAM-X-1m-/260929145173?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3cc096c955#

How about some galvanised cable tray, self supporting so it could go any which way, sturdy enough to have isolators, fuse holders etc attached to it, and can attach ally heat shield where it's near hot exhaust bits.

 

cheers,

Pete.