Immersion Heaters And Extension Cords

[SeanAU]

Quick question that someone more electrically inclined than me might be able to answer.

I've recently bought a 2400w over-the-side immersion element (the tobins one) and will be using it through an RCD. My question is to do with using these in conjunction with an extension cord.

Would using a cheapie extension cord (say a $5 3m bunnings jobbie, still rated @ 10A) result in a lower output at the element than using a more 'heavy-duty' extension cord (assuming there is such a thing, and it's not just marketing). By heavy-duty, I'm still talking about a 10A rated cord.

I guess taking it a step further, would there be an appreciable difference in the element's output between using a cheapy extension cord and no cord at all?

Cheers,
Sean.

 

[fcmcg]

Quick question that someone more electrically inclined than me might be able to answer.

I've recently bought a 2400w over-the-side immersion element (the tobins one) and will be using it through an RCD. My question is to do with using these in conjunction with an extension cord.

Would using a cheapie extension cord (say a $5 3m bunnings jobbie, still rated @ 10A) result in a lower output at the element than using a more 'heavy-duty' extension cord (assuming there is such a thing, and it's not just marketing). By heavy-duty, I'm still talking about a 10A rated cord.

I guess taking it a step further, would there be an appreciable difference in the element's output between using a cheapy extension cord and no cord at all?

Cheers,
Sean.

Bloke,
I'm not a sparka-trician , but from what i understand , your lead is still 10 amps regardless....BUT i did experience a cheap lead starting to melt ( on the female end ...where the element plugs in) when running my 2400 element... i did get kinda hot and i guess it was pulling a fair load...
I now use a heavy duty lead ( still 10a)and my RCD...no such probs anymore...
Cheers
Ferg

 

[alford_j]

Any extension cord will reduce the output of the element compared to no extension cord- but the difference may be small. It all comes down to the resistance of the extension cord. If it is say 10% of the resistance of the element then it will make a significant difference. I just measured the resistance of my "heavy duty 20M extension cord" as 2 ohms. My calculations say if I used this cord with your element I would get 2044W out of my element and 171W in my extension cord. That is a significant loss- I'm surprised now I have measured it.

My answer would be: Use an extension cord only as long as you need and use a reasonable quality one- a cheap one half as long may have less loss than a long quality one. BUT the cheap lead may also be poorly made and melt- I have seen that too.

Alfie

 

[SpillsMostOfIt]

I used to brew with two 2400W over-the-side elements from Tobins.

As an experiment once, I hooked one up via a normal domestic 3 metre 10 Amp extension cord and the other via an extension cord made from 15 Amp cable. It was 6 metres in length.

There was a noticeable visual difference in the anger of the boil immediately around the elements, with the 15 Amp cable being the angrier. The 10 Amp cable got quite warm - worryingly so for me. This is all predictable if you apply Electrical Science to the matter, but there is no place for that here in a home brewing forum.

I would advise that although a cable might be rated at 10 Amps, that doesn't mean that you should aim to draw 10 Amps through it for hours at a time. In the grand scheme of things, the cost difference is not huge and you're going to save heaps of money over your gas-burning colleagues.

 

[SeanAU]

Thanks for the info. I'll pick up a heavy duty (1.5mm^2 wiring) cord for the element. The cheapy cord was either 0.75mm or 1mm and got pretty warm, and was probably choking the element back.

Cheers,
Sean.

 

[welly2]

To open up an old thread, I have a question related to this. I've just been testing my boiling kettle with a 2400w fixed element and a 2400w hand held element. I used a pair of cheap $5 extension cables to reach the mains. They both fired up and started boiling the water BUT the 2400w fixed element kept on tripping the fuse. Not sure if it was down to the cheap extension or I was drawing too much power from the mains? It looks like I have a couple of different circuits in my apartment (at least I have four different fuses in the fusebox). Any thoughts?

Edit. Just further to this, found two different mains circuits and apparently I was running both elements on a single circuit so perhaps I need to use the two mains points and maybe that'll sort out the problem?

 

[Dae Tripper]

Welly you should run them on two different circuits, you would be overloading a singe circuit. Generally the circuit breaker will be 20amps for a power circuit and your pulling 20 already. Turn one off to identify the separate circuits and you should be fine, till someone wants a cup of tea aswell.

 

[welly2]

Welly you should run them on two different circuits, you would be overloading a singe circuit. Generally the circuit breaker will be 20amps for a power circuit and your pulling 20 already. Turn one off to identify the separate circuits and you should be fine, till someone wants a cup of tea aswell.

Ok brilliant, I'll do that then. Thanks very much! And the tea drinkers can wait.

 

[MastersBrewery]

I'd also like to add cheap extension cords while rated to 240 volt 10 amp, I'd say this is a peak load for them. I've found such cords over prolonged use at full load will heat up quite a lot this is due to resistance and will likely mean your heating elements aren't receiving the full 10amps and nasty shit happens when electrical cables get too hot. The big green shed and Masters both sell heavy duty (1.5mm core) 10 amp cable. I know it isn't cheap but well worth the time and trouble.

MB

 

[MAX POWER]

I run a similar setup in my apartment. I put little coloured stickers on each powerpoint identifying which circuit each is on. Helps avoid tripping the fuse. Also easy to avoid using the same circuit as fridge, tv etc.