Arcing - What affects size of arc when switch is opened?

1. Nov 10, 2013

Crazyhorse2882

When an electrical circuit is opened or closed there is an arc between the terminals/buss that the switch or breaker is connecting or disconnecting and the arc is greater depending on the amount of voltage. My question is, is the arc greater when there is a resistance/load on the circuit? I'm guessing yes, but what is the effect and how could you calculate it?

2. Nov 10, 2013

Staff: Mentor

You have to consider the whole circuit to determine that.
In general, inductances (especially coils), large switching voltages and large currents will increase the amount of arcing you get.

3. Nov 10, 2013

OmCheeto

Without a resistance/load, you wouldn't have a circuit in the first place, and therefore wouldn't have an arc at all.

4. Nov 10, 2013

Crazyhorse2882

So then if a main breaker was closed outside of a building feeding equipment inside the building but their individual circuits were open then there would be no arc as that breaker closed? There would be voltage but no current and my understanding is that it will arc

5. Nov 10, 2013

OmCheeto

That is correct.
No, it will not arc.

6. Nov 11, 2013