Low Voltage yard lights transformer buzzing loudly

[Smitty7265]

Hi all. First time on this forum. My apologies if this was answered but I've searched and searched and really didn't find anything that might relate.

I have a low voltage (Malibu) yard lighting transformer supporting up to 300watts of lights. it's plugged into a GFCI outlet and another outlet is adjacent to it. The whole circuit is switched with a digital timer switch. I plug this transformer to the GFCI outlet, turn it on and it buzzes really loud to a point where I don't want to connect it to this outlet.

Plugging it in another outlet, different circuit, does not exhibit the issue and is very quiet.

I hear related issues where the neutral could be loose but the issue is I'm not sure where to check being one of the 2 outlet's, breaker or switch, or understand the overall circuit to understand if it's even wired correctly. is there any help anyone could provide?

As an example I plugged in a leaf blower and the pitch is noticeably lower than plugging it in on a different working circuit/outlet.

Thank you for any help provided!

[HayZee518]

The gfci - all it does is measure the current going into the external circuit and what returns along the neutral. Inside the gfci are two coils or "toroids" that connect into the electronic circuit. they are current transformers with two leads coming out of them.
The switching circuit that opens the circuit should a fault occur is a triac. It may be this that is causing the buzzing. Unless the transformer is a real cheap device, it shouldn't be making all that racket. the iron laminations that form the core are insulated from one another. Copper wire is wound around the form twice. one winding consists of a heavier wire for the primary and smaller wire forms the secondary winding. you are stepping down 120 ac to 24 or 12 volts ac. There is no reason to use a gfci for a lighting circuit. A gfci is used for personnel protection like for a lawn mower or a blower, anyplace a human can touch an appliance. the lighting is protected because of the stepping down function as the two windings are separate from each other.

[Smitty7265]

The house came with a GFCI outlet on this circuit. The circuit consists of 1 GFCI outlet, 1 regular outlet and 1 switch.

The low voltage transformer for the lights only buzzes plugged into this circuit on the GFCI outlet and the non GFCI outlet. The transformer does not buzz plugging it into another outlet on a different circuit.

So my assumption is something on the circuit.

[HayZee518]

I read your first posting and offered an explanation of how a gfi functions.
I then stated to use another outlet that is not gfci. It completely went over your head.
GFCI's protect personnel.
use the non gfci outlet.