bilge pump

richardjawilson · 17 August 2006, 18:12

I currently have a Rule 500 gph auto bilge pump and wish to add another on the same circuit. Is it just a question of wiring it to the existing power supply, and if so, will I need to put put in a bigger fuse, ie twice the rating???

The reason for having a second pump is that the current pump jammed after ingesting a small bit of debris, and as I was away for a few days it caused a fair bit of havoc because my Rib sits very low in the water and needs a fully working pump!!

richard

Poly · 17 August 2006, 18:42

In theory you should be able to add a new pump in PARALLEL to the existing one. BUT you should check the wiring can cope with double the load. You may need to increase the fuse - it depends on the current the pump draws. The fuse will need to be larger than the sum of the two individual pumps.

richardjawilson · 17 August 2006, 22:07

ok, thanks for that, i'll check what amps it first pump draws and go from there.

regards richard

timw · 17 August 2006, 23:06

Richard,

Not related to bilge pumps, but is yours the RIB on Cadagon Pier, Thames new there this season?

richardjawilson · 18 August 2006, 00:42

It sure is, I think you are moored up at the Hurlingham if I'm not mistaken. The rib replaced a very damaged Gladitor 4.8, 60 hp boat in May of this year following a collision with a large semi floating log/tree branch at 34 knts. The rib is new to me but was originally moored in Newhaven. I have seen your rib at full flight a few times but generally I have been travelling the opposite direction!!

richard

timw · 18 August 2006, 08:35

Richard,

Good to see another RIB on the river. Mine was at Chichester until 3 years ago then I moved it to London and have been on Hurlingham Jetty for the past 3 years but wintering in South Dock Marina.

Now I know it's you we'll stop for a chat next time. Am out most sunny weekends and the occassional evening.

Mines grey and called Snapper.

Tim

steedthrust · 18 August 2006, 08:41

Could you not run another feed & fuse to the new pump. If one pump develops a fault and trips the fuse you have no pumps.

richardjawilson · 18 August 2006, 13:48

good thinking Steedthrust, I think thats the best solution. I was looking for a quick fix but I guess the only way to do it is properly.

Snapper I guess I will bump in to you shortly.

regards richard

jyasaki · 18 August 2006, 17:54

I would wire it completely reduntantly. Too many possibilities of fuse or wiring problems. Two separate systems are much more reliable than two systems with a bunch of stuff in common.

jky

yoyo · 18 August 2006, 21:33

Any fuse used should NOT be greater than the individual pump rating. this could cause you big probs.

Poly · 19 August 2006, 11:21

Quote:

Originally Posted by yoyo

Any fuse used should NOT be greater than the individual pump rating. this could cause you big probs.

I don't think I agree with you. The fuse is really there to protect the wiring not the pump. If a pump starts drawing more current than it should it has already developed a fault. If an individual pump starts to draw more power than its rated for it will probably burn out the motor pretty quickly, and any "serious" fault (such as a short) is likely to blow a fuse even if it is double the size recommended for the pump on its own. It is not possible to run two pumps on a fuse that is the correct size for one (unless it was oversized in the first place).

In a different environment you would probably choose to put a "master" fuse at the console that could cope with both loads and thenindividual fuses on each pump. BUT putting fuses in the bilge is not really a great idea - as you will struggle to get them water tight, and IMHO fault finding is much easier if all the fuses are in the same pannel.

However, I agree that redundancy is a better idea, but more effort and cost required to install it all.

richardjawilson · 21 August 2006, 22:09

thank you for all for your thoughts on my bilge pump wiring, the information is more than appreciated.

regards richard

Rogue Wave · 22 August 2006, 03:25

redundant wiring marine cable and fuses not MCB's also think about a bigger Bilge pump. when joining the cables from the pump to the cables from the supply doit inside one of these boxes screwed to the transom and use silicone to sea cable entries

http://www.tlc-direct.co.uk/Products/LB9025.html

this stuff is handy also

http://www.tlc-direct.co.uk/Products/TLSAT19.html

Andy Gee · 22 August 2006, 08:52

It would be better to run another complete system in, and then mount your second pump higher than the first, to act as redundancy if your first pump should fail.
HTH
Andy

richardjawilson · 22 August 2006, 13:24

Andy, thats what I have just done. The secondary pump is fitted higher up and working off a separate circuit. So hopefully thats the best solution for me.

regards richard