Immersion heater off 13A plug

[wc1966]

Is the following safe?

3m 1.5mm core into 3kw immersion heater? The heater is set on a timer switch to operate maximum 1 hour per day, seems to get a little warm as you'd expect. Are these timer switches a risk running at high load, there's a lot of crap on the market, any recommendation?

I see there are extension leads on the market with 2.5mm core, would I be better to get one of these and use the cable? Cheers

 

[johnb2713]

Is the following safe?

3m 1.5mm core into 3kw immersion heater?

It should be ok, it can carry much more than the 12 amps or so needed for the immersion.

The heater is set on a timer switch to operate maximum 1 hour per day, seems to get a little warm as you'd expect.

It will depend on the quality and the rating of the switch, if it's getting warm youre wasting energy.

Are these timer switches a risk running at high load, there's a lot of crap on the market, any recommendation?

Dont buy cheap, buy good quality, I've used some from Screwfix which have been good on a 16 amp load, no heating etc, they dont have relays inside them either, all the switch is electronic which helps reliability and efficiency

I see there are extension leads on the market with 2.5mm core, would I be better to get one of these and use the cable? Cheers

Not necessary, though, if I was doing the job I would have wired it in 2.5mm2 from the start.

 

[Murdoch]

Short answer is yes BUT there are so many cheap plugs in the market don’t be surprised when it starts distorting

 

[wc1966]

It should be ok, it can carry much more than the 12 amps or so needed for the immersion.


It will depend on the quality and the rating of the switch, if it's getting warm youre wasting energy.


Dont buy cheap, buy good quality, I've used some from Screwfix which have been good on a 16 amp load, no heating etc, they dont have relays inside them either, all the switch is electronic which helps reliability and efficiency


Not necessary, though, if I was doing the job I would have wired it in 2.5mm2 from the start.

Actually it was the cable getting a little warm.

In terms of the switch I'm just using a mechanical one. I was trying my Givenergy smart switch but it seems a bit flakey, can't get the schedule function to work and I've had the timer crash the app. With the former there's no risk of it getting left on for an extended period

 

[binky]

I would describe that set up as ' pushing your luck'.

You want heat resistant cable, ideally 2.5mm and a 20Amp double pole switch, not a plug and socket.

 

[wc1966]

I notice you can buy a extension cable with a 2.5mm cable that could be trimmed down

https://www.orbitalfasteners.co.uk/products/14m-extension-lead-240v-13a-heavy-duty-2-5mm-cable
Maybe a safer option, less heat on the cable and less losses

 

[Murdoch]

I notice you can buy a extension cable with a 2.5mm cable that could be trimmed down

https://www.orbitalfasteners.co.uk/products/14m-extension-lead-240v-13a-heavy-duty-2-5mm-cable
Maybe a safer option, less heat on the cable and less losses

That isn't heat resistant ...........

 

[Richard-the-Ninth]

You can buy heat resistant 3 core 2.5mm flex by the metre Click me (Other suppliers are available)

 

[johnb2713]

I notice you can buy a extension cable with a 2.5mm cable that could be trimmed down

https://www.orbitalfasteners.co.uk/products/14m-extension-lead-240v-13a-heavy-duty-2-5mm-cable
Maybe a safer option, less heat on the cable and less losses

A 3 metre length of cable, 2.5mm would dissipate 3.84w, 1.5mm2 6.39w, i hardly think thats significant.

2.5mm2 would be better I agree, mainly for it's mechanical strength etc.

 

[poni]

Yes heat resistant cable is a must, 1.5.or 2.5, the choice is yours(if its an extra long run 3m+ then 2.5 might be better,
but I would use a 20A double pole switch or a switched fused connection unit, instead of a plug and socket even the good one fail, I have seen so many fail due to a poor connection between the plug and socket ( back in the 50's I think it was common to fit a plug and socket in the airing cupboard )