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Thread: DARKROOM - Electric Questions

  1. #1
    Jeffery Dale Welker
    Join Date
    Sep 2006
    Mesa, Arizona

    DARKROOM - Electric Questions

    As we emerge from COVID restrictions and I recover from a recent surgery, completion of my humble home darkroom can again become a high priority.

    I'm expanding an existing, and underutilized, pantry to serve as my home darkroom. While the pantry currently has two switched can lights in the ceiling, there are no electrical outlets. A few feet away is a 220v outlet in my garage that was originally intended to allow using a welder. It is on it's own dedicated 200v circuit with breaker. My thought is to keep the existing switched can lights and feed all other electrical needs by converting the dedicated 220v circuit to 120v.

    My questions are as follows;

    1. Will normal 20 Amp 125-Volt Duplex GFCI outlets work for my enlarger and related darkroom uses?

    2. Should I consider adding surge protection or a stabilizing power supply?

    3. In the future, will changing my enlarger head from the Dichro 45S colorhead to a cold light LED source (i.e Heiland) create any issues that I should be planning for now?

    To help with your answers, I've acquired and intend to install a wall-mounted Beseler 45V-XL with the Dichro 45S colorhead and GraLab 451 solid state digital timer. In addition to the enlarger arrangement, I'll have two or three old school GraLab 300 timers, a Jobo CPP2, Thomas Safelight, print inspection light, etc. I've attached a copy of my floor plan for reference.

    Your wise counsel and suggestions are appreciated.
    Attached Thumbnails Attached Thumbnails Darkroom Floorplan v.1.jpg  
    "I have this feeling of walking around for days with the wind knocked out of me." - Jim Harrison

  2. #2
    Tin Can's Avatar
    Join Date
    Dec 2011

    Re: DARKROOM - Electric Questions

    Should be fine

    I prefer a breaker box GFCI and grounds to all metal

    The Heiland should draw enough power to run old timers

    I have had trouble with DIY light load LED and old timers

  3. #3
    Eric Woodbury
    Join Date
    Dec 2003

    Re: DARKROOM - Electric Questions

    You can split your 220Vac circuit into two 110Vac circuits with a common return. This is legal. I wouldn't bother with extras such as surge or OV or other protections. Nor stabilization. I'm using an LED source now and it works fine on regular old juice. My darkroom doesn't take much power except for a space heater and small water heater. All my lights are LED. Stereo doesn't take much. Mostly, it is a matter of having lots of outlets. If I were you, I'd get some nice switched multi-outlet power busses. And depending on your white lighting requirements, consider using track lighting.

    Be safe and keep one hand in your pocket.


  4. #4

    Join Date
    Mar 2005
    Newbury, Vermont

    Re: DARKROOM - Electric Questions

    Assuming that you are the only person using your can split that 220 circuit into two 120's...and dedicate one of those to just your enlarger bench. In other other uses for that circuit. Then, the remaining 120 can be dedicated to everything else in the darkroom, helping to ensure minimal interference with line voltage on your enlarger circuit...which is very important!

    Do be careful that various devices which employ heating elements (film dryers, dry mounting presses, electric room heaters), should all be isolated from your enlarger circuit!

    I also happen to own a Heiland VC LED head for my Zone VI enlarger...and so far its been extremely consistent in output, without the employment of any additional voltage stabilization scenario, excepting the aforementioned enlarger circuit isolation. I do have a voltage stabilizer for my Beseler 4x5 enlarger...but really don't use that enlarger all that much since the acquisition of my Zone VI.

    And yes...normal 125 volt gfci's will be fine for your darkroom, and, if below grade (typical for a home basement) likely required by your local electrical code. The only exception would be if you were using electric motors with high starting torques (like a large diameter chop saw) - which can throw a gfci on those occasions when other outlets in that circuit are also in current (ha!) use. Not a likely scenario in your darkroom.

  5. #5
    jp's Avatar
    Join Date
    May 2009

    Re: DARKROOM - Electric Questions

    A normal 20a circuit with GFCI should be fine.

    One thing you might consider is using track lights instead of cans. I have a tracklight for red safelight LEDs. Then I can point them where I want them. Use separate light switches.. One for normal light, one for safelights. Sometime I'll have a tracklight for normal lighting in the darkroom, but that's less useful than the safelights.

    Another thing I did was (with relays) lock out (disconnect) the main light when the safelight is on. You could probably do it with a 3-way switch on the safelight and daisy chain the normal main light switch behind that.

    The welder circuit might/might not have a neutral. If it's just two hots and ground (like a hot water heater), it's not suited for your repurposing. If it has two hots, a neutral, and a ground, it's good. Either change the breakers it connects to in the main box to 20a duplex or have a subpanel where the welder outlet is located.

  6. #6
    Tin Can's Avatar
    Join Date
    Dec 2011

    Re: DARKROOM - Electric Questions

    I have 2 cheap 5 button remotes, not wifi, tiny battery lasting 5 years so far, they switch 4 circuits
    One is mounted outside the DR door, just in case I misplace the primary

    2 safe lights, one fan and big overhead all bounce off the ceiling so I never need to climb a ladder again

    Since I process film in tanks with lids, I can safely switch anything, as needed

  7. #7

    Join Date
    Jul 2006
    Collinsville, CT USA

    Re: DARKROOM - Electric Questions

    Present darkroom is my 4th. Measures 8' x 17' which was determined by a pre-existing wall.
    Two 20 amp circuits both on GFIs: Was an overcall in retrospect. Two 15 amp circuits would have been more than I needed. Plus had to use 12 gauge wire. With 15 mp circuits I could have used 14 gauge wire which would have been a lot easier to work with.
    I installed 2 water valves to shut off the water supply to the darkroom when I wasn't using the darkroom - good idea. Thought to do the same for the two electrical circuits - bad idea... At different times of the year I run either a humidifier or a dehumidifier in the darkroom. I shut off the power to the darkroom several times forgetting that I had also shut off the power to the humidifier or the dehumidifier. Removed the switched and capped the 4x4 box with a plate.
    16 total outlets: Good pre planning of where to place them but I have racks of print drying screens located under the sink and forgot to place an outlet behind them to wire up 2 computer fans (also would have included a wall switch for them) which would have greatly decreased my FB print drying times.
    One 2'x4' and one 2'x2' recessed fluorescent lighting fixtures: replaced them with LED fixtures which greatly increased the amount of light.
    Use an ARISTA high intensity UV light box on a timer. Very rarely it pops the GFI. Have yet to figure out why. An electrician told me this happens sometime with very sensitive GFIs. Should have planned better for the print inspection light's location gut not worth changing.
    Thomas Sodium Vapor safelight which I have had to lower its light output.
    Built in a red safelight in a wall on one side of the sink which I have yet to use.
    Print timers and power supply are located on a shelf above the dry side's counter: Allowed me to totally free up the counter space. Great when loading ULF film holders.
    Densitometer located in my "work" space: No heed to be located in the darkroom.
    Radio and CD player located high on shelves. Had to run it and more off a wall mounted hidden outlet strip. Hadn't planned on this but worked out better than if I had included one more wall outlet.

    Ass I had always told my students: "Mistakes are teachers in disguise"

  8. #8
    Drew Wiley
    Join Date
    Sep 2008
    SF Bay area, CA

    Re: DARKROOM - Electric Questions

    All depends on if you might hypothetically scale up to higher voltage or higher wattage equipment further down the line, especially if you contemplate something like 8x10 color enlarging. It's easier to bring in 240 voltage early on, rather than retrofit. But 20A 115 is ample for what you currently have in mind. I'm personally nitpicky about getting good quality CFCI outlets and breakers from reputable electrical supply houses, and not from the usual Cheapo Depot type suspects - it really can make a huge difference in reliability. Likewise lighting. But any kind of wattage glutton like routine air conditioning will be way less expensive if run on a dedicated 240 V circuit.

  9. #9

    Join Date
    Nov 2017

    Re: DARKROOM - Electric Questions

    move the safelight and fan switches away from the other switches, you don't want to mix those up.

  10. #10

    Join Date
    Apr 2009
    Seattle area, WA

    Re: DARKROOM - Electric Questions

    I'm not clear on what you mean with respect to the 220v outlet and converting it to 120v. Ya you could split it to two 120 breakers, but if that outlet was for a 50 amp welder circuits that would mean your feed wires would be huge 6 gauge cable. Best thing to do is either leave the 220v alone and put in new additional breakers with dedicated new romex runs, or take out the 220 breaker and outlet and use the existing wire to pull new romex through. 6 gauge wire is hard to work with, is not something you need and mixing cable sizes on a circuit is bad practice.

    Side note- the 220v outlet in a garage would be really useful for an Electric Vehicle charger if you ever intend to upgrade your car.

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