9 replies to this topic

[LukeH]

Hi,

I'm hoping someone can help me regarding the use of an immersion heater.

I want to know of it is safe to put a 13amp plug on the immersion heater and plug it into a digital timer? (not a specific immersion timer)

My immersion is rated at 3kw, which should draw 12.5amps (3000 / 240volts = 12.5). My digital timer is rated at 13amps at a max load of 3120watts.

The plug socket is on its own feed from the fuse board which is rated at 15amps.

My main concern is whether it's safe to use a 13amp plug and timer or should I purchase a hardwired immersion timer?

Thanks in advance.

Luke

[Stevie W]

Hi,

Its more usual (and safer) to hard wire your immersion heater through a 20A fused outlet. Doing what you're proposing is not that safe as you are running everything at its max current limit with no margin.
In my experience, running anything that draws 3kW on a 13A plug/socket outlet is ok whist all is new and tight. Sometimes cables can come loose in the screwed terminals due to the 50Hz mains which can in extreme instances can vibrate screws loose.
This causes a heat build up because the connection now has a higher resistance but is still trying to pass 3kW of power.
I've watched a fuse box at work catch fire due to a loose terminal on a circuit that was passing current near to its 100A limit....scarey!!
Hope this helps.

Steve.

[Bungle]

^^that^^

you running very close to the 13a plugs limits and for the amount of time a immersion heater is on for things could start getting very hot

i would stick with the hard wiring and fit a hard wired timed

on a side note have you heard about part P of the building regs ?

[Gaffer]

Part p only applies if you use the new grey cable ;0)

Im agreeing with the rest, for the effort thats involved its just as easy to hardwire it in

[LukeH]

Thanks for the replies. Yes I am aware of part p building regs.

The main issue is that I live in a rented house with an oil boiler. I would like to make use of the immersion in attempt to reduce the amount of oil I buy.

The immersion is currently hard wired into a switch, no fuse, on its own breaker at the fuse board.

I think I'll do things the right way and get a hard wired immersion timer.

Cheers, Luke

[Bungle]

Part p only applies if you use the new grey cable ;0)

LMAO can you post a link to back up this statement

[Bungle]

Thanks for the replies. Yes I am aware of part p building regs.

so your ok to test the modified circuit and issue a certificate + don't forget to notify building control of this work if the immersion is in the bathroom or kitchen

[mini-luke]

Part p only applies if you use the new grey cable ;0)

LMAO can you post a link to back up this statement

Perfect, I won't need to do mine then! Oh dear...

[Gaffer]

http://www.diydata.c...ctric_cable.php

cables turned grey in 2004 before the introduction of part p in2005.

Circuits in grey cable obviously would have been installed after part p and would therefore need to be certified by a competent qualified person (well new circuits etc).

On a serious note though, its not recommended and part p is there to protect and comply with current legislation so its best to do it properly

[blacktulip]

from what i hear at work its best to hardwire it.