Finding the hot wire on a 12v pool light

[pool-light-repair]

Hi there!

I'm in the process of replacing my Hayward Color Logic light with another light and I'm trying to determine which wire is hot, and which is neutral.

From the Hayward logic board/circuit board, the pool light wire goes into an Intermatic transformer (model PX100), converting 120v to 12v AC.

When I cut the pool light I was expecting a black & red wire, or at least two different color wires. However, they are both yellow and neither one has any discernible markings on it.

I used my multimeter to test the votage coming out of each wire, but no matter which way I put the two wires to the multimeter, they are both testing at 12v.

Similarly, when I touch the black wire on the multimeter to ground, I'm getting a reading of a few volts from both wires when touching the red cord to either.

In other words, it appears both wires are exactly the same.

Am I doing something wrong in my testing? This is my first time replacing a pool light, so this is new to me.

Thanks in advance for any advice you can provide!

 

[ajw22]

Welcome to TFP.

There is no polarity to the 12V AC circuit. Both wires are equal.

You do not have a hot and neutral wire like in a 120V circuit.

It is like a 240V circuit with two hot wires except at 12 volts.

 

[pool-light-repair]

Thanks very much for your reply! Does that mean it's safe to attach the hot and neutral wire from the new 12v light to either of the wires?

 

[ajw22]

Thanks very much for your reply! Does that mean it's safe to attach the hot and neutral wire from the new 12v light to either of the wires?

A 12V AC light does NOT have a hot and neutral wire.

The wires have no polarity and can be attached either way.

 

[pool-light-repair]

Got it, thanks! I think it was the new light's wiring schematic that threw me off the most (attached).

It shows a N and L wire (I presume neutral and live) going to the light (circled in red), and the colors of the new light's wires are blue and red, so I was expecting to have to find the hot wire.

Thanks again for the help!

 

[ajw22]

If you do not understand US Electrical Standards you should not assume when doing electrical work. That diagram is incorrect in many things it shows. Whoever drew that was likely foreign.

For example, a black wire does not go to a N (Neutral).

US electrical color coding standards are black, red, and blue all denote hot wires. White wires are neutral. Green wires are ground.

And observe that the electrical plug drawn is not a US 120V plug.

Assuming manufacturers instructions are correct can be dangerous if you do not know what you are doing.

 

[pool-light-repair]

Ha, good point – lots wrong with the diagram.

I certainly trust my multimeter more than the paper, but after having conflicting information I wanted to double check.

Many thanks.

 

[JamesW]

https://www.kmccontrols.com/wp-content/uploads/kmc_documents/AN0604D-RevB.pdf

How do 24VAC transformers work

Transformers come in all shapes and sizes and in different voltages and current ratings. These mechanical room devices, 24VAC transformers, change one voltage to another, but how do they work?

www.hpacmag.com

 

[Methuselah]

Doubtful, but possible there is continuity between primary and secondary intended for the neutral side so if a light housing is grounded a hot side short to housing can blow a fuse.

Anyway, diagram is at best misleading.

With power disconnected use ohms setting on one primary wire to one secondary wire. Don't touch probe tips while doing it - meter should not read any different than with leads disconnected if it's ok to disregard the drawing's "suggestion" that "polarity" matters.