Electric Hlt Tripping Safety Switch

[geoff_tewierik]

Hi all,

I just fired up the HLT for todays brewing and it's tripped the safety switch. I reset everything and it happened again.

My first thought is there is an issue with the element and it'll need replacing.

Does anyone else have some suggestions as to what may be the issue?

The unit is a Fowlers Vacuola 28L Urn for preserving bottle, it runs on 240V and has a 2400W element.

Cheers,

GT

 

[enoch1973]

Try on a different power point? Got may other appliances on?
Turn some off... The house I'm renting trips the safety switch if there's to many things running on the power points.
Apart from that, time for a new Urn?

 

[rclemmett]

Does it trip the safety witch as soon as you turn it on?

 

[dent]

The RCD trips, depending on the type, on there being a greater than 30 milliamp difference between the current flowing from the supply, to your power points, and the neutral coming back from the power points through the RCD again, and back to the supply.

The RCD trips because the assumption is, if the current isn't flowing back through the neutral, it must be flowing somewhere else - like through a person, down to earth.

Some (most?) elements will have an earthed conductive outer tube, filled with insulating ceramic, with a conductive core which is actually the part that has the power going through, heating up. If the insulating ceramic gets wet, which it shouldn't, it can cause the RCD to trip since there is current flowing now to earth. Even if the outer core is not earthed, the metal of the kettle should be.

Only thing to try there is run the element for a while with no water in there, let it get orange hot, then try again - this is to attempt to dry out the insulation. But if it is leaky it will likely happen again.

Either that or you have some other issue in the thermostat wiring or whatever.

 

[Murdoch]

Residential RCD`s need to trip when 30mA is "lost or leaked" from the circuit (within 300mS)
A Class I device/appliance (appliance with a wired earth) is allowed up to 5mA "leakage" before it is deemed unsafe & condemned
It does not take many appliances leaking 5mA to get up close to the 30mA trip value
Many RCD`S will trip at a lower level than 30mA as well which increases the problem
These "trips" are known as "nuisance trips"
Plugging your urn in may well be taking the total mA of "leakage" in circuit to the trip point but each appliance individually could be fine
I would suggest unplugging everything from a power circuit then plug in your urn
If its the only thing on that circuit & it still trips you have a problem with the urn
If not you may have too much or many leaking devices on that circuit
This will at least let you know if your urn is any good

 

[geoff_tewierik]

Thanks for the info guys.

I did try a different wall socket, same thing happened.

Rob2, it does trip as soon as I turn it on, so I turned the thermostat down to 0, rest the safety, turned the urn on at the wall and then turned the thermostat around until it turned on to heat, the light flickered on and then it tripped the safety switch again.

Not sure if I can run the urn empty, or whether it's got a boil dry fail safe built in. Any way to check that?

Will have to wait before I try and pull everything out and just run the urn, SWMBO just chucked a load of washing on.

BTW, turns out we have only two circuits for appliances in the whole house, now to work out whether it's one for the top floor and one for the bottom floor (where the urn is) or whether the sparky got creative when the previous owners reno'd downstairs and used both circuits for downstairs.

Cheers,

GT

 

[Paul H]

Thanks for the info guys.

I did try a different wall socket, same thing happened.

Rob2, it does trip as soon as I turn it on, so I turned the thermostat down to 0, rest the safety, turned the urn on at the wall and then turned the thermostat around until it turned on to heat, the light flickered on and then it tripped the safety switch again.

Not sure if I can run the urn empty, or whether it's got a boil dry fail safe built in. Any way to check that?

Will have to wait before I try and pull everything out and just run the urn, SWMBO just chucked a load of washing on.

BTW, turns out we have only two circuits for appliances in the whole house, now to work out whether it's one for the top floor and one for the bottom floor (where the urn is) or whether the sparky got creative when the previous owners reno'd downstairs and used both circuits for downstairs.

Cheers,

GT

Hey Geoff,
I have a similar issue with mine as far as I can't turn the toaster or kettle on whilst I have the HLT on, best to get a sparky in.

Cheers

Paul

 

[Bribie G]

If it's a Crown or Birko then heating it while dry is not an option due to its cutout switch. Try drying it as far as possible then give it a good session in the sun for a few days or make a 'tent' with a sheet and a frame (couple of chairs, clotheshorse whatever) and use a fan heater to bake it for an hour or so, with the bottom 'plate' of the urn removed.

Mine also trips the ELCB if I have a kettle or even fridge running on the same circuit. It's a 2400 Birko. However doesn't trip if the other appliance is on another circuit.

 

[LethalCorpse]

Is it the circuit breaker that's tripping (there's one of these for each circuit) or the RCD (usually just the one for the whole panel, with a "test' button on it). If the former, it's tripping because you've got too much running on the circuit. If it's the latter, the element is dead.
Why dick around with running it dry, sticking it in the sun, etc? If the element is buggered (including wet), it needs to be replaced.
If you had a multimeter, you could measure the resistance between the pins at either end of the element and ground, would give you a good indication - should be pretty much infinite resistance. I'm guessing you don't have one of those.
If it's simply tripping because you've got too much running on the circuit (the wife's washing, fr'instance), you just need to make sure there's nothing else with significant current draw running on the same circuit at the same time. This should be easy to test - flick the breaker off on one circuit then go around to each point with a desklamp.

 

[geoff_tewierik]

It's the RCD that's tripping, therefore it's the element (my first thought). Thanks for the confirmation LC, will swing past a sparky suppliers on Monday and grab a new element.

 

[geoff_tewierik]

FWIW I was hunting around on ebay for a new element and found the same unit as mine up for grabs, in case anyone wanted to know what it looked like.

http://cgi.ebay.com.au/Fowlers-Vacola-Elec...=item1c12220652