The Home Machinist!

That will work just fine, although I don't know if that would violate code, or not. If you had to do any work on the light, you'd have to disconnect the machine at the source to ensure safety (or disconnect where it was wired at the machine).

Harold

The light needs its own fuse on the primary side of the transformer.

Thanks for the info Harold and John!

John, could I just put a fuse in-line with the power cord?

Harold_V wrote: ↑Tue Aug 21, 2018 3:57 pm If you had to do any work on the light, you'd have to disconnect the machine at the source to ensure safety (or disconnect where it was wired at the machine).

Harold

That would be fine as I basically unplug the machine after use anyway. Just a silly habit I have with all my equipment.

RSG wrote: ↑Tue Aug 21, 2018 7:56 pm Thanks for the info Harold and John!

John, could I just put a fuse in-line with the power cord?

Yes.

Thanks John,

So that leads me to my next question, looking on line for what size fuse I need I found a formula of Watts divided by volts. So my 50 watt bulb divided by 220 volts should be some where around .25 amp fuse. Does this sound right?

RSG wrote: ↑Wed Aug 22, 2018 9:34 am Thanks John,

So that leads me to my next question, looking on line for what size fuse I need I found a formula of Watts divided by volts. So my 50 watt bulb divided by 220 volts should be some where around .25 amp fuse. Does this sound right?

Use 1 amp. A .25 amp fuse is guaranteed to eventually blow at .25 amp.

You are basically protecting the wiring from damage in this case, not the bulb.

Thanks for the info John and Glenn.

That's what I'll do!

I am thinking of my mill, the RF30 which as a light bulb that looks like a factory thing. It used 110V lamps and I suspect taps one of the hot legs to the mill (220V single phase). I'm sure that is hard wired and not fused. Perhaps that is OK, as it is form almost any house lamp with a plug, not to have a fuse, maybe because it is integral to the system?

So, is it the transformer that necessitates the fuse or the lack of a plug?

On my CNC, I tap one hot leg there too, but have a power strip with a circuit breaker on it. That is where I plug in my Ikea 5V LED lamp. It uses a wall adapter (transformer), and perhaps that little plastic brick has an inaccessible fuse? It is plugged, but perhaps I would have hard wired that transformer.

It is true, I think the fuse is not to protect the bulb, but to protect the wiring and transformer.

This became interesting to me when I acquired a 10 outlet strip. It has 10 30A receptacles (I think those are 30A, with the one prong turned 90°. The plug has a prong turned 90°.
It's great because now I can plug in all my 30A devices into that 10 outlet power strip, and draw up to 300A through that cord, but the 30A fuse at the service entrance will protect it from even just two 30A loads, or enough more than just one.

A lamp is its own protection, as the resistance of the filament restricts the amount of amperage that can be carried. If voltage is increased, more amperage is forced through the circuit, at which time the filament fails----so it is nothing less than a fuse---one that puts out light.

Fuses are used to protect wiring. They do not protect components, although there are likely cases where they do. Bottom line is that's not why they're used.

H

ctwo wrote: ↑Wed Aug 22, 2018 3:14 pm and draw up to 300A through that cord,

A good example of the fuse being used to protect the wire. There's no way in hell the cord used could conduct that kind of amperage. It would burst in to flame instantly if it could, and did. Wire size is way too small to do so.

H