Old 12 volt light confusion

Jump to latest Follow Reply
J

Juggernaut1103

0
Jul 24, 2015
54
STAMFORD, CT
Alright, so I have an old pool, and everything i see makes me shake my head. When we bought the house, i guess they did what they could to get it up and running to sell. There was no GFCI breaker for the pool light, installing that this weekend. the converter box is by the electric panel in the house and then the wire runs out to a j box then down and into the pool housing. I got on a step stool and looked over into the converter when i was in the basement. Im very confused by this converter, one side has the 120v connections, but then on the other, there are only 2 wires connected with a wire nut, and then two others that were just sitting there (pictures attached). Is something wired wrong here? i bought a new 12 volt bulb to put in the pool because the other one burnt out (it was a basic flood light they put SMH), but now i'm skeptical if everything is done right, or if they bypassed something to just make it 120v. This light is old and i cant find any info on it online. I was thinking the wires not used are probably wires that would be used for 13 or 14 volts, and the two that are connected in fact make it 12 volts.

View attachment 78371View attachment 78370View attachment 78372
 
Last edited:
J,
The schematic diagram of your stepdown transformer has only 3 wires on the secondary output. The lead wire with the red wire nut on the bottom is 0V, while the other lead wires on top are labeled 12V and 13V respectively.
You can verify if the transformer is operational using a DVM set to read AC Volts between 0V and 12V or 0V and 13V. Or set the meter to read 20 VAC if you don't have the auto ranging. When connecting a low voltage AC light fixture, the 0V and 12V lead wires are interchangeable. And of course, the green wire must be tied to the electrical ground, regardless.
 
that confuses me, because the light did work before, if its hooked up for 0 volts, i'm not sure how it needs to be hooked up for it to work with my 12 volt light. im not an electrician but very handy. im not good with transformers though, and i really don't want to go and pay hundreds to have some wires switched around. do i need to switch over to the 12 volt wire from the 0 volt? How did the light previously work then, lol, or is it wired correctly. you seem to know what your talking about Meadow.
 
J,

Are you sure that transformer is being used at all? I can't see where the wires from the pool light are connected to the transformer...

Show us a pic from a little further back showing where the wires from the pool light comes in.

I am "assuming" that you have not disconnected or connected anything so far.

Thanks,

Jim R.
 
looks like they bypassed the transformer when they went to get the pool up and running. Makes me angry i spent so much on a 12 volt light because of what the light housing said.

i have the large light cable running into the back of the box, then there is one set of armor clad running to the transformer, one to the breaker box, not sure where the other goes, ill have to check, then there is nothing in the large pipe running to the transformer. question is does the transformer still work? how do i test it? how do i hook it up for 12 volts if it does work?

View attachment 78488
 
J,
The first picture in post #1 indicates the Transformer is bypassed. There isn't any wires connected to the secondary winding. Are you sure your existing pool light is 12V or 120V AC?

I know you have a Voltmeter. Before you measure the transformer, please make sure to set the Voltmeter to measure AC and not DC! Connect one of the test lead to 0V (the pigtail with the red wire nut) and the other test lead to the wire on top labeled 12. Apply 120V AC power to the transformer. If the transformer is good, you should read 12 Volts AC.

To connect a 12V AC light fixture to your existing step down transformer:
1. Connect the green wire to the electrical ground.
2. Connect one wire to 0V (red wire nut).
3. Connect the other remaining wire to 12V (top of transformer, labeled 12)
4. Do not use the other wire, labeled 13. Just capped it using wire nut.
5. Secure all the connections using wire nut.

Please let me know if you have any questions.
 
Thanks Meadow, really appreciate the help and instructions. So the light housing in the pool actually says 12 volts on the housing, that's the only reason i knew. Its def wired currently for 120, because there was a regular style house bulb in there when we moved in. Ill get going on this soon and report back how it goes.
 
So I tested the transformer, i'm pretty sure I know which wires are correct, when I tested I got 11.5volts (wires with green tape and blue tape). I want to verify these random wires (white tape), i'm pretty sure they are just for a ground, but the wire used is old armor clad and there is no separate ground wire used, and the ground coming from the pool light is grounded to the metal junction box, everything is ground through the armor clad wiring and boxes. Both wires with white tape go into that weird looking circle thing on the bottom of the image, those wires are also silver like aluminum, compared to the blue and green taped wires which look copper. Is it correct to assume those marked with white are not needed?

IMG_1898.jpg


Also the wire coming from the pool light is heavily insulated (wire connected to GFCI outlet, dont worry adding a GFCI breaker). Can I just connect them (pool light wires) to number 12AWG and run it up into the transformer and make my connections to the blue and green taped wire? Also, it looks like I have 12 gauge running everywhere minus the wires going to the light switch in the family room and outside that turns the pool light on, those wires look to be 14. I know you are suppose to have 12 for a 20amp circuit, anyway that 14 gauge might be alright? If not should I just return the 20amp GFCI and put in a 15?

IMG_1894.jpg

Really appreciate all the help. Again, I just want to make sure I have my ducks in a row before hooking it up the way I think it goes.
 
J,

First off, I am not an electrician. I can only provide you very limited instructions on how to wire a low voltage pool light fixture based on my own experience.
The 12V light fixture comprises of 3 wires, this could be white, black and green. In your case, you need to connect the white wire to the secondary output of the transformer (blue tape) and the black wire to the green tape accordingly. There might be other junction box in between, who knows! The green wire must be connected to the electrical ground, metal junction boxes, metal enclosures or metal conduit are considered ground loop.

From what I can tell, the 2 wires with white tape are just for ground connection and has nothing to do with the transformer. Somehow, they used black wire instead of green, wrapped around the transformer enclosure mounting bolt or screw. You can loosen the screw and investigate what lies underneath the metal washer or perform a continuity test.

The pool light switch must be installed between the AC feed and the transformer. The light switch should be able to turn on/off the incoming AC supply to the 120V primary winding of the transformer.

Unfortunately, the 2nd picture tells me nothing but just a bunch of electrical wire connections inside a junction box with what looks like a service outlet. Only you or the onsite electrician can identify and trace the wiring. Anyway, it might be for your best interest to engage an electrician or perhaps others can walk you through to achieve your goal.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Juggernaut1103 said:
Figured i would share, those wires i had wrapped in white tape, they weren't ground wires. this light transformer is so old it was for a round screw in fuse. surprised the transformer still works, might look into buying a newer style transformer.

View attachment 80510
Click to expand...
J, thank you for the clarification. In that case, what is the fuse for? Were there any external wires connected to the pigtail?
Again, it has nothing to do with the transformer and I see no reason to get another. If it was me, I'll go ahead and wire the light fixture as described above. But it's your call.

update: ok, I think I got it! A quick look at the transformer diagram, one might think the fuse is built-in to the secondary winding! What's odd is that, the diagram on the transformer is a picture of the whole enclosure. If the transformer was removed, I'll go with the diagram and assumed there is an internal fuse in the secondary winding! :scratch: I'll certainly ignore that fuse if obsolete, but it's just me!
 
Last edited:
I went ahead and wired it all up per our previous convo, im wondering if it has to do with how old the fixture is. when i think 12 volts, i think of my car stereo days, and fuses in a car. im wondering if the 12 volt line out (blue tape) from the transformer is to be connected to one of the fuse wires (white tape), then the other wire wire would be connected to the wire headed to the light itself. When i originally looked at the transformer, the 12 volt wire was indeed hooked up to one of the wires that runs into the fuse box. they may have just bypassed the transformer all together because they didn't feel like finding a fuse. just talking out loud. Everything i come upon i find interesting with how old the pool is. they legit did what they could just to get it up and running, and thats it, now im dealing with all the headaches.
 
Juggernaut1103 said:
I went ahead and wired it all up per our previous convo, im wondering if it has to do with how old the fixture is. when i think 12 volts, i think of my car stereo days, and fuses in a car. im wondering if the 12 volt line out (blue tape) from the transformer is to be connected to one of the fuse wires (white tape), then the other wire wire would be connected to the wire headed to the light itself. When i originally looked at the transformer, the 12 volt wire was indeed hooked up to one of the wires that runs into the fuse box. they may have just bypassed the transformer all together because they didn't feel like finding a fuse. just talking out loud. Everything i come upon i find interesting with how old the pool is. they legit did what they could just to get it up and running, and thats it, now im dealing with all the headaches.
Click to expand...
Bingo! Yes, your existing 12V light fixture was originally wired to the transformer exactly the way you described. But there is no reason to bypass and install a 220V incandescent bulb on a low voltage light fixture. They can actually jury rig a replacement fuse holder.

But anyway, I would assume the transformer is getting the AC feed from the breaker or GFCI. My wild guess, your 12V LED bulb is rated at 35 Watts and that would equates to only 2.92 Amps. That's a tad less compare to the basic car stereo. You should be good.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply