Cable size for electric toilet, does this sound right?

longjohnsilver

longjohnsilver

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Fitted a new Vetus electric loo over the w/e to replace the old leaking Jabsco model. Had to install a new pressure pump, a Jabsco 2.9 gal per minute as well as the loo itself.

Manual says on long flush 2.2 l should be pumped through. However I get a max of 0.5l. Mate has exactly the same toilet and Jabsco pump and he gets the full 2.2l or thereabouts. Spoke to Vetus and they tell me that they think my power cables are too small, should be 6mm. The existing cables are pretty beefy, not sure of the exact size, but they were fine for the old Jabsco unit. The cycle is always completed, just with very little flushing water. The pump by itself delivers plenty of water when disconnected from the loo.

I suspect I'm being fobbed off, cos I can't see how having thicker cables will deliver more water to the loo as the pump is completely remote from it. And 6mm cables sound very thick to me, but I'm no sparky. Any suggestions or thoughts?
 
longjohnsilver said:
Fitted a new Vetus electric loo over the w/e to replace the old leaking Jabsco model. Had to install a new pressure pump, a Jabsco 2.9 gal per minute as well as the loo itself.

Manual says on long flush 2.2 l should be pumped through. However I get a max of 0.5l. Mate has exactly the same toilet and Jabsco pump and he gets the full 2.2l or thereabouts. Spoke to Vetus and they tell me that they think my power cables are too small, should be 6mm. The existing cables are pretty beefy, not sure of the exact size, but they were fine for the old Jabsco unit. The cycle is always completed, just with very little flushing water. The pump by itself delivers plenty of water when disconnected from the loo.

I suspect I'm being fobbed off, cos I can't see how having thicker cables will deliver more water to the loo as the pump is completely remote from it. And 6mm cables sound very thick to me, but I'm no sparky. Any suggestions or thoughts?
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To advise on the cable size we need to know the system voltage (12 or 24), the current consumption in amps of the pump and the length of the cable run from the supply to the toilet.

It is surprising how heavy cables often have to be on 12 and 24 volt systems to avoid excessive voltage loss. The longer the cable the heavier it has to be.

When you have 240 volts it does not matter if you lose a few along the way but when you start with only 12 you cannot afford to lose more than a fraction of a volt.

You could check the voltage at the pump terminals while it is operating to check that it is getting the full voltage. Bad connections can be a cause of low volts just as well as inadequate cable size
 
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6mm sounds small to me; although not on a 24v system. What Vic says, although as a clue, my Jabsco is installed on 16mm2 cable, albeit a long way from the distro.
 
Is the Jabsco pump ( about 5 amps at 12 volts I think ) running at the same time and off the same supply as the toilet.

I am finding some very high current figures ( 25 amps at 12 volts) for Vetus toilets !


30 amps total with a cable run of say 15 ft is going to need 20mm² cable!


I hope with those sort of currents for 12 volts this turns out to be a 24 volt installation when 6mm² will be adequate for a 15 ft run
 
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Ok guys, thanks for those thoughts. It's a 12v system and yes the pump is running off the same supply as the toilet. So maybe the water pump is running slow when the toilet is doing its thing. I will investigate further and get some heavier duty cable installed. So maybe I was being unfair on Vetus.
 
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