Can some one please tell me that on a extension lead there is a Warning! telling you about " maxium current.
Why is it for example that there is a difference between maxium current " wound and fully unwound?
And what causes it please?
2007-08-19 07:38:16 · 7 answers · asked by Artx 1 in Home & Garden ➔ Do It Yourself (DIY)
I wont repeat, both the answers referring to induction are correct. If in doubt, unwind all the cable before use.
2007-08-19 21:55:37 · answer #1 · answered by jayktee96 7 · 0⤊ 0⤋
The answers regarding induction are totally wrong.
The cable has two cores carrying the current and carrying the current in opposite directions. There is therefore no effective inductive effect. Transformers are wound with single cores and EMF relates to Voltage and not Magnetism,
The hazard comes from the heating effect of the current in the cores. A core within the drum coil has nowhere to dissipate it's heat as it is surrounded by other cores at the same temperature. The heating effect is proportional to the load, so if you were using it to drive a small lamp unwinding the coil would be less important than if you were powering a heating element.
Regards
Iowbill
2014-11-19 16:16:47 · answer #2 · answered by Anonymous · 0⤊ 0⤋
when a cable is coiled it causes induction just like a magnet. To create an induction uses current (just like in an electric motor , it has a mile upon mile of wound copper wire ,creating a magnetic field ) so if you plug in a 10amp appliance for example ,when cable is coiled then the other 3amps would be used to create the the induction thus using 13amps .Now if the cable is uncoiled then the current used would only be that of the appliance thats plugged in.... Also heat is created in a coiled cable and to get heat you also use current , the same as an electric fire. so always uncoil the cable or the fuse / cicuit breaker will trip , never try and over-ride the fuse/circuit breaker as they are designed to break the circuit for safety reasons . so heat doesnt build up and cause fire to the wiring . hope this explains it for you.
2007-08-19 17:03:19 · answer #3 · answered by averontollcross 1 · 1⤊ 0⤋
When you pass a current through anything there is a heating effect. When the lead is fully unwound, the heat can be dissipated to atmosphere along the length of the cable, if it's not fully unwound it just warms up the rest of the cable. So if the cable is used wound up, you reduce the maximum current to reduce the heating effect. You can't destroy heat, only move it.
2007-08-19 14:46:05 · answer #4 · answered by Anonymous · 4⤊ 0⤋
The correct answer is 'induction',In an extended lead there is minimal EMF-(electro motive force-or magnetism!)which is the priciple of how transformers work.
A transformer works by inducing a current in a secondary coil reacting with the primary coil-using the EMF principle.
Thus if you use an extension lead whilst coiled it acts as an transformer and induces further currents within it self-the main upshot of this in an extension lead is heat buildup-the lead could well-and I have seen it-start to melt.
Rich.
2007-08-19 15:27:50 · answer #5 · answered by Anonymous · 1⤊ 0⤋
I think it's because when it is wound up it can't cool down as quick. Basically wond up generates more heat in the cable.. I think. Thers prob a more technical answer though.
2007-08-19 14:47:30 · answer #6 · answered by chicken pops 3 · 0⤊ 0⤋
your worried about nothing really...just go by the maximim current.....
2007-08-19 17:25:04 · answer #7 · answered by Anonymous · 0⤊ 1⤋