[Neil Williams]

I've now modified my scorpian by fitting a 3kw immersion heater through the back and went went quite well with no leaks.
Problem is when I plug it in it trips either the RCD on the extension or without the RCD trips the switch on the fuse box, so I guess 3KW from zero to three is just too much in one go.
How do I get around this? Would fitting a 'reostat' similar to a dimmer switch in action do the trick, so I could gradulary increase the power consumption. 

[Dave_Lee]

Doesn't a house immersion heater have a higher capacity fuse/Trip device. Have you tried it by plugging it in to a cooker/oven specific socket. If it works on that, then that's probably the reason.
Dave.

[Neil Williams]

Luckily my own house still runs on the old fashioned fuse wire system and as such doesn't blow it. Yet the house I did today runs on these super new ultra sensitive trip boxes and even when I plugged it into where the kettle was in the kitchen, it tripped it.
As such it draws the same power as a standard kettle but I guess these must have something inside them that doesn't in a nano second draw the full 3KW, hence why I'm wondering if anyone else has modified a machine and come across the same problem, and how to get around it.

[M.Acorn]

You want a contact relay,growers use them to turn on big sodium lamps,contactor relay takes the brunt of the surge

[JS2]

Neil

What's the current rating of the overcurrent breaker e.g. 16 A ?  The RCD is probably 30 mA

Pete (JS2)

[Mr Dvae]

sounds to me like you might have a leak to earth, and a good job if it is better than thru you!

[Titan]

R.C.D Residual Current Device.  Detects leakage to earth, so I would say that your heater is faulty or some thing is wired the wrong way round if you keep tripping out. You need to get a sparky to at least pat test the appliance.

M.C.B Mechanical Circuit Breaker.  Depending on the rating i.e. 16 amp will click off when you exceed more than 16 amps to protect the cable from overloading and melting like a fuse basically.

1kw = 4.5amps approx, so 4.5 x 3 = 13.5amps, if you was overloading surging you should blow your fuse in the plug first as your average house plug ring is regulated at anything from 16 amp to 32 amp depending on if it is a ring or not. Cooker sockets are usually regulated 40 amps.

Hope that this is of some help.
Good luck.

[Neil Williams]

Thanks for the info Jon.
The unit is brand new and I have wired it up correctly.
It won't be the first time I have had trouble with the power of the actual machine on some very new properties, infact the ship job the other week was a right mare because the scorpian kept blowing the cabin fuses.
What I will do is get a qualified sparky to do the checks just to put my mind at rest on that point.

[Titan]

Its always hard to say exactly what it could be without being able to test / and work on the machine but thought that I would mention the basics.
I have come across heaters that have had faults from new before so you could just be unlucky.

Best of luck any way.
Cheers Jon

[Tony Gill Carpet Smart]

Neil is there a common ground / earth point on the machine sounds like it is going to earth some where or is it just wired to a seperate lead and plugged in on its own.

Tony

[fenman]

We have been using 3kw immersion heaters for years to heat up water.
Always used them with a wired in rcd plug and never tripped electrics in a house or commercial property.
If there was a problem with them they would trip out whenever a housholder switched them on.
It does seem likely that yours is faulty or wired incorrectly

[Neil Williams]

Sorted
Got the multimeter out and found the fault in the cable which clearly got mullered when the rear door slammed shut in high winds we've had recently.
That got me organised into checking all the other electrical items, which resulted in fitting new cable to both rotaries and needing to cut about 2 foot off one of the extension reels.
Lesson to be learnt: Fit RCD's to everything.

[Titan]

Nice one ! 

[Adam Fearnley]

How do you test the wire with your multimeter?  I have the same problem sometimes.