I wish to install some Kodak safelights to the darkroom ceiling, the older Model C with a Pull Chain Cord Switch Control. They will be mounted firmly on the Kodak brackets.
Actually wired with the original 2 prongs plug. Do I need a 3 prongs plug to have the protection from the Ground Fault Circuit Interrupter Outlet?
As wet hands can be possible, what is the best material for attaching to the Pull chain to make it longer? coton cord?
Thanks for the info.
My Lumen project http://ginetteclement.com
What material is used for the housing of the safelights - metal or plastic? The concern here is that if the safelights have metal housings, a failure within the safelight could cause the housing to become energized and present a shock hazard. If metal, the truly correct answer is that they should be rewired to include a ground connection between the metal housing and the building ground. That way, any failure within the safelight that causes the housing to become energized would be protected by the GFCI outlet. Important - that means that you need a three-conductor cable in addition to a three-prong plug so that the building ground can extend to and connect to the metal housing of the safelight. If plastic, that isn't necessary.
However, if the ceiling is high enough that a person standing on the floor cannot touch the safelight and its metal housing, then it may be technically OK to not rewire the safelights. But understand that there are two issues here - what is correct in engineering terms, and what is required by local codes. I don't know what Quebec codes require.
In the US, a fan or light that is over a bath tub or shower must be protected by a GFI receptacle. The theory is that in the event of a failure in the fan/light, steam from the tub/shower could form a conducting path that could cause a person in the tub/shower to receive an electrical shock. I would not expect there to be any steam in a darkroom, so I don't think that scenario applies. But ultimately, your local electrical inspector is the only person who has the authority to interpret the application of the code to this situation.
I would definitely want to put some kind of insulating material between the pull chain and the cord that you actually touch when you switch the lights on/off. Heavy cotton or hemp cord is fine, or light-weight plastic rope.
I'm not really comfortable with the idea of pull-cord switches in a darkroom. My darkroom is wired to have the switch next to the door serve as a master switch for everything in the darkroom. Then, I have a bank of switches at the enlarger to turn off the overhead white light, and also to turn on the receptacles that feed the safelights.
Do not use nylon cord if there is an electrical hazard, it will carry a charge. Polypropylene is the recommended material for handling high voltages. For sure rewire if the design allows it. And I agree about using a wall switch if you can put one in. I actually have my safelights controlled through the enlarger timer and only gets powered up during a print session.
I'm 99% sure the answer is "no"; you do not need a 3 prong plug for GFCI. They work by detecting the power being grounded by you. Since I'm not an electrician, I won't say 100%.Originally Posted by Ginette
I assume, however, that the gfci itself is grounded. Some very old wiring may have used 2 wire instead of 3 wire cable.
This doesn’t answer your question.
It’s what I do.
Install a GFCI Breaker in your main box that feeds everything in the darkroom.
Then I use wireless remote controls to turn safe light and white lights on and off.
I have ‘Zap’ brand. There is a red led on the plug side I gaff tape cover.
I don’t rewire anything.
I'm not sure what US regulation has to say about this, but in most codes, if you rewire appliances, they are not covered by their certification anymore. So if this light is made, tested and certified for use with 2-wire, then use 2-wire to connect it.
A GFCI does not to be earthed itself to function, but the earth connection is needed for the test button to work. They work by comparing the current in the live and neutral wire. If there is a current imbalance larger than their design current, they break the circuit.
Expert in non-working solutions.
Another solution is to have a plug or connection to the safelight that is turned on and off by a wall switch rather than the pull chain. Makes it so you don't have to touch the safelight fixture at all.
” Never attribute to inspiration that which can be adequately explained by delusion”.
Keep in mind that risk posed by a nylon or cotton pull cord on a safelight plugged into a gfci pales in comparison to the risk posed by your enlarger and (presumably) metal cased timer.
And will "box" mounted gfci outlets, the downstream outlets can be wired so that they are protected or not protected. If you're not sure, best to test with a device like this.
Yes, once a year check all GFCI outlets with that type device.
Plug it in and live another day.
All of the above answers are helpful. To be clear though you do not need a grounded outlet for a GFCI to be wired up. (See Havoc's comment above.)
Best solution would be to rewire the whole circuit --the others are more of less compromises or work a-rounds and may be very satisfactory
for your purposes.
My house, built in the 1950's uses a two wire system. When rewiring anything in the house, if possible, I use 3 wires (the third being the ground) from the inside electrical panel.)
FYI, I have been a building inspector (ICC certified) for the past 14yrs for a county in SC.
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