Immersion Resisitance

JOHNPT

If an immersion element of 3KW is reading a resistance of 24 ohms is it faulty? What resistance should it read?

Thanks in advance for replies

Rev. BlueJeans

Depends. Megger is the best way, but folk don't often have those

If it's tripping rcds or the like it's probably buggered. Bath is low, sink is higher in terms of resistance, but all that will tell you is the element is intact, not its insulation.

2011

3000 watts devided by 230 volts gives a current of about 13 amps. Devide 230 volts by 13 amps and you get about 18 ohms. So your 24 ohms is close enough I would imagine. All figures are very approximate.

I assume that you are measuring between live and neutral?
My own 3kW immersion is 26 ohms between N & L (across the element)

This does not mean that you do not have an insulation resistance issue though! As Rev. says a meggar is the best way to test this. It should give a live or neutral to earth reading in the megga ohm range.

davelerave

As already said ,a resistance measurement will tell you bath/sink.But for troubleshooting you need a megger

JOHNPT

Thanks that makes sense. My immersion had a resistance value of 24 ohms but it was still triping the ELCB every time. Can anyone recommend where to buy a megger at a good price. Im not looking for a top of the range megger.

Thanks if anybody has any suggestions

davelerave

you were buying one one 6 months ago.!!
a cheap one will do for troubleshooting

JOHNPT

I know i was going to but never bought one. Dont know much about meggers and probably wont be using it that much but would still like to have one for situations like this. How much would i need to pay or where should i look. Thanks

Pete67

Your local electrical wholesaler should have a basic megger, but it would be a lot cheaper to buy a new RCD and an element - either one of them is faulty or there is an earth leakage fault in the wiring. Most likely culprit is the element though. A decent megger with a 500V test voltage will be around 500-600 Euro, 1000V range will be a bit more.

davelerave

i spent around a 100 on the last two.I'm usually fairly broke unfortunately and drop them often.I bought them from cpc

JOHNPT

Ok thanks for advice will have a look out for one