Voltage rating of wire

[ElectronicsR]

Hello,
If we increase current in wire it burn if we increase voltage what will happen in small zero pcb wires??

 

[Harald Kapp]

The voltage withstand capability of a wire does not depend on the thickness of the wire. The thickness of the wire is only relevant for the max. current it can carry.
Responsible for the max. voltage that can safely be applied to a wire is the insulation (thickness, material). Generally:

• A wire with thick insulation can withstand a high voltage regardless of the thickness of the wire.
• A wire with thin insulation can withstand a only low voltage regardless of the thickness of the wire.

'wires' on a PCB (called traces) are not extra insulated (solder stop coating is not a valid insulator). Therefore you neeed to increase the distance between wires when the voltage between them increases. There are several standards covering these requiremenets, notably EN/UL 61010-1.

 

[ElectronicsR]

Hello,
Thanks for reply.
So, in large kv rating wire what type of insulation we need?
and why insulation is important for higher voltage, does electron cross the insulation?

 

[Minder]

High Kv cable requires a suitable insulation to prevent breakdown, if you go to the Cable manuf sites, they usually have technical information on their respective cable ratings.
Beldon is one such large manuf.
M.

 

[Minder]

You will need a cable with a manuf. insulation rating according to the EMF your system is using.
See Insulation breakdown.
https://en.wikipedia.org/wiki/Dielectric_strength
M.

 

[duke37]

If you look at the wires in a telephone cable you will see that they are fairly thin. Mains cables are thicker and have a secondary insulation layer. Car ignition cables are much thicker than either. It is all due to the voltage in the wire.
Polyethelene is a common insulation, if you are rich, you can go to PTFE.

 

[Harald Kapp]

It is all due to the voltage in the wire.

Sorry to disagree, but in this case the wire thickness or diameter is due to the current, not the voltage. A telephone cable carries a minuscule current comparet to the high current a car's wiring has to provide during e.g. a cold start of the engine.

 

[davenn]

Sorry to disagree, but in this case the wire thickness or diameter is due to the current, not the voltage.

primarily, duke is referring to the thickness of the insulation in which he is correct
just wasn't worded as clearly as it could have been, but I understood what he was getting at
and with that it is all related to the voltage in the wire that needs to be isolated/insulated


Dave

 

[Harald Kapp]

just wasn't worded as clearly as it could have been

Sometimes it shows that i'm not a native English speaker
But why should the insulation of a car's wiring (@12 V) be thicker than the insulation of a mains cable (@115 V or @230 V)?

 

[davenn]

But why should the insulation of a car's wiring (@12 V) be thicker than the insulation of a mains cable (@115 V or @230 V)?

specifically he said "cars ignition cables" and I immediately thought of the wires between the coil to distributor and sparkplugs
where the insulation is very thick .... many kV's and relatively low current


D

 

[Harald Kapp]

cars ignition cables

O.K., I see. Thanks for putting me on the right track.

 

[duke37]

Yes, I did not describe the wire diameter in a clear way. Harald is better at english than most native speakers.
Interestingly, car starter connectors are always known as cables not wires.
I think that the insulation of the wiring of cars or combine harvesters has to not only provide isolation but also to withstand vibration, a robust covering is then necesary. Flexible mains cables have a secondary insulation covering. In the past single insulated twin bell wire was adequate.

Recently, I have been winding a coil using wire, not cable even though it has insulation on it.

Edit:
I just had a look at the thread title, it is "Voltage rating of wire"

 

[ElectronicsR]

thanks for reply help

 

[Minder]

thanks for reply help

Incidentally just in case you might think of using Automotive Hi tension plug wire the conductor can vary in composition.
The vast majority of cores are conductive carbon wrapped with fine copper wire. Other cores wrap wire around a magnetic material.
Conductive carbon can break down over time,
Older autos had actual copper conductor.
M.