120V AC to 12V AC transformer question

[MrRedPants]

I have an old transformer in metal mounted electrical pool box (GFCI inline).

Has 120V AC input and its outputting 11.3V AC per my multimeter. It's used to power LED Pool light (s) - which flicker on / off - which I assume is the tranformer. If I use a 12V power supply temporarily with enough wattage, the light lights without issue.

I have two lights right now - first I just bought rated at 30W. The spa light is a hayward universal colorlogic - I think it's rated at ~70w.

So, the question - if I replace transformer with a 'typical' pool light transformer - usually rated at 300W and range from $75 - $150. These transformers make sense when the lights were incandescent. With LED the wattage requirement is so much less. There are waterproof transformers that seem a lot less (for example 60W for $30)

What am I asking? Are these typical transformers required with LED lights and GFCI circuit? I don't want to skimp obviously, but I also don't want to pay $100 just because that's what we've always done

Interested in your feedback!
I'm probably overthinking this purchase as it's probably once every 5 year purchase.

 

[Charlie Bezzina]

Hi. Your total load is currently 100 watts. You therefore require a transformer with a minimum rated output of 100watts.

The next time you replace a light you may need to reassess, alternatively you might plan ahead and double your requirement and get a transformer with rated output of 200watt now.

 

[wgipe]

My understanding is that pool rated transformers are electrically isolated for safety while landscape lighting transformers are not. I would wait until one of the folks here with more knowledge of that comments before you buy anything.

 

[MrRedPants]

My understanding is that pool rated transformers are electrically isolated for safety while landscape lighting transformers are not. I would wait until one of the folks here with more knowledge of that comments before you buy anything.

Thanks! I will. I'm likely just going to bite the bullet and buy the appropriate one. I'm realizing electricity and water and children is not really something I should be cutting corners on

 

[JoyfulNoise]

There’s no issue using a transformer that’s rated at a higher power output. You never know, you may find more uses for it (additional landscape lighting, etc).

And yes, “pool” rated transformers have their primary and secondary windings more robustly isolated, typically with a grounded metal shield between them, and an ungrounded secondary winding so that the danger of a primary-to-secondary short or stray ground currents is a lot less likely to happen. A standard 12V transformer for typical non-wet applications will not have those safety features.