Electric toilets

[senator]

Hi All

One for the electricaly minded, I am in the proccess of installing an electric macerator type TMC 12 volt toilet into Clandestine.

Finding that the thing ran at 20 amps I was not silly enough to try and pick up a feed from the wiring close to the Heads instead running a feed from the main isolator, thing is this means a wiring run of 4.5m, can anyone tell me what thickness wire I should be running to feed the thing?

Ian

[Antares_9]

Don't forget when you do the calculation that it's not actually 4.5m but 9m Ian, i.e. the total run of cable unlike in a chassis return. Unless the calculater you use already allows for it that is of course.

[senator]

For some reason the link won't work but the total run is 4.5m Isolator to switch, 1.2m switch to toilet, 1.7m toilet to netrual

I have used 6mm but think that may be a bit light, was expecting to pick up a feed from within the helm consol but only the anchor winch and ignition were big enough, the anchor winch was on huge cables so I did not want to break into them and I thought the ignition was a no no, didn't fancy a jammed loo knocking the engines out at sea. the 6mm was anticipated for max 3m run total.

Ian

[senator]

Thanks Pete,

Only problem is I don't know what drop or resistance is acceptable. Is 5% OK assuming that the toilet will work at 11.5 volts and what about resistance, is that not the thing that causes all the cables to melt and set fire to the boat, meaning everyone needs to populate the dinghy on the run to southwold thanks to an oversized turd?

Ian

[Antares_9]

Most cabling on modern boats is expected to give around a 3% drop Ian, from a purely practical point of view the electric lavies and holding tank macerators (for emptying tanks at sea only) I have seen are

6 or 8 mm sq. As the current draw is very intermittent and would only last for only a few seconds on the toilet macerator, unlike a holding tank one which can operate for up to 3 mins or so it would probably be OK. The acid test is to run it for a minute or so and see if the cable gets warm. Not very scientific I know but then does the macerator draw 20 amps on start?, continually?

Then there’s also other factors to be taken into consideration, not all cables are equal, 6mm thinwall is higher rated than the old thicker wall 6mm for instance.