Why can't an extension lead be used on the charger supplied?

[Filmcrew]

Hi, does anyone know what happens if you use the charger with a 13amp extension lead. I regularly visit someone but the lead is not long enough.

 

[Regulo]

"Hi, does anyone know what happens if you use the charger with a 13amp extension lead"

As long as it can handle 13A, and is weatherproof if used outdoors - nothing.

 

[HHL]

"Hi, does anyone know what happens if you use the charger with a 13amp extension lead"

As long as it can handle 13A, and is weatherproof if used outdoors - nothing.

Something will happen.... it will charge.

 

[Regulo]

"Hi, does anyone know what happens if you use the charger with a 13amp extension lead"

As long as it can handle 13A, and is weatherproof if used outdoors - nothing.

Something will happen.... it will charge.

I meant, nothing bad will happen - but you knew that, didn't you?

 

[jaapv]

However, should anything happen, the insurance can make difficulties, as the length of the lead to the box may not exceed 50 cm. I use an extension lead regularly.

 

[JSC]

If the extension lead is one of the coiled types, make sure that you uncoil it completely before using it. If you leave it coiled, the high current for a long period can cause a coiled cable to heat up (due to the electro-magnetic effect) which can be dangerous (obviously). Also, the longer the extension cable the higher the additional electrical resistance that will be added. This will result in a drop in the voltage at the car end of the circuit and will result in a longer charge time.

So, the overall message is that you can use extension cables, but they must be adequately rated, waterproof, uncoiled, and that your charge time might go up a bit

Hope that helps

 

[Grigou]

If you leave it coiled, the high current for a long period can cause a coiled cable to heat up (due to the electro-magnetic effect) which can be dangerous (obviously).

Not sure of that.
I don't think that the impedance is so much higher when the cable is coiled. I am speaking about a 10 to 20 m cable, not about a 1 km cable of course

I think that the cable can heat because the heat (produced by the resistance) inside the coils can't be cooled properly.

Sorry for my English, again.

 

[maby]

If you leave it coiled, the high current for a long period can cause a coiled cable to heat up (due to the electro-magnetic effect) which can be dangerous (obviously).

Not sure of that.
I don't think that the impedance is so much higher when the cable is coiled. I am speaking about a 10 to 20 m cable, not about a 1 km cable of course

I think that the cable can heat because the heat (produced by the resistance) inside the coils can't be cooled properly.

Sorry for my English, again.

I did look at that post and question it - I suspect that the issue is more resistive than reactive - but without getting out a calculator and my old course notes from university I cannot be absolutely sure!

... and don't apologise about your English - my French is just about good enough to order a meal - certainly not to discuss topics like this!

 

[Bladevane]

The effect is because the coiled cable forms an inductive loop and creates an electromagnetic field which will generate heat. All coiled leads should be unwound before passing high current through them.

 

[Tipper]

It's only 10A max, so hardly high current!

My own explanation about coiled cables is that the conductor size is always reduced to the bare minimum for maximum profit therefore it heats up due to resistance and needs to be uncoiled so it keeps cool.

The important thing is water proofing the extension socket.

I use and extension cable all the time but the car end is a proper external waterproof socket mounted on the wall adjacent to the car, so semi-permanent. The other end uses a 13A plug and socket on the garage power ring protected by rcb, etc. It is a separate circuit to the rest of the house electrics. I can also use a plug-in power meter that reads amps and watts, etc.

 

[maby]

The effect is because the coiled cable forms an inductive loop and creates an electromagnetic field which will generate heat. All coiled leads should be unwound before passing high current through them.

We understand coils, magnetic fields, inductance and reactance - I think we are just questioning whether or not a dozen turns with no iron core would have sufficient inductance to produce any noticeable heat at 50Hz. If we were talking about radio frequencies, the answer would be very different.

My gut feeling is that the effect would be too small to be noticeable and the heating must be purely resistive, but I really would need a calculator and my old lecture notes to be sure.

 

[jaapv]

But even resistive heating can be substantial and a coiled lead especially in a container can have trouble with heat dissipation.

 

[anko]

The effect is because the coiled cable forms an inductive loop and creates an electromagnetic field which will generate heat. All coiled leads should be unwound before passing high current through them.

As you have the "plus" and the "minus" side by side all the way, I don't wonder if this is true.

I think the problem is that the heat generated by the inner windings cannot escape easily because of the outer windings.

 

[JSC]

Hi there. I'm happy to accept that the heating could be caused by either the electro-magnetic effect or lack of cooling, but I know it's real as I've detected significant warming on a 15m extension lead when used with power tools for any time without uncoiling it. So, whatever the reason, it's a good idea to really unwind (he says as he kicks back on the train home )

All the best

 

[Filmcrew]

Hi, thanks for your replies. I was worried that the charger unit was sensitive. The manual says never use an extension. What you've all said makes perfect sense. Thanks.

 

[ansellrk]

On all UK coiled extension leads it must display on it the maximum coiled and uncoiled power that can be drawn through it.

As a PAT tester I can absolutely confirm that you should always uncoil the extension lead especially if drawing high amps. Follow the guidelines on the actual cable, they will be clearly defined.

You will be surprised by the difference my 25m cable is 720w wound and 3120w unwound. So wound you should only draw 3 amps through it!!