220V Indicator Lamps

[samc]

Bought these for a new build

Mostly using 10 gauge wire for 30amp/220v, if I want to downsize wire into these lamps (20 ma) do I have to fuse them to protect them? Or am I just better off sticking with 10 gauge?

 

[bbognerks]

You don't need 10 gauge into the lamps. They won't ever pull enough amperage to require that size wire. 12-14 gauge is fine. No need to fuse it unless you want to save those $3 lamps in the case of something going terribly wrong.

Personally, I didn't fuse my 220v lamps.

 

[MarkInOhio]

You don't need 10 gauge into the lamps. They won't ever pull enough amperage to require that size wire. 12-14 gauge is fine. No need to fuse it unless you want to save those $3 lamps in the case of something going terribly wrong.

Personally, I didn't fuse my 220v lamps.

The idea of the fuse is not to save the lamps. The idea of the fuse is to prevent a fire from the wiring overheating if something goes terribly wrong WITH THE LAMP. Let's say the lamp shorts out and you have 14-gauge wire and the only circuit protection is a 30-amp breaker. That wire is going to get red-hot and melt.

Generally speaking, the wire gauge should be large enough to carry the amount of current allowed by the circuit protection.

 

[bbognerks]

I'm 99.999% sure that if there was ever an over-voltage to the lamps, the tiny little LED or the circuitry for it would burn out before the wire would catch fire. At that point, the LED/circuitry is the fuse and you have to replace it.

Now, really the only other thing that can happen is that the plastic separator between the lamp connectors could fail. This would result in a dead short, so it would trip the breaker in milliseconds. If you want to be 100% safe, then by all means fuse the lamps. All you really will be accomplishing is protecting the lamps. Everything else inside the box is just as susceptible to the same scenario of catching fire, even the connections to the fuse holder.

Think of it this way. Are there fuses on all of the light bulbs in your house? It's a matter of what you are wanting to protect really. If you want to protect every single item in your control panel against over-load/over-volt, then yes, you'll need to fuse every item individually.