I have this mess of wires in a junction box of a stucco house (built 30 years ago). Couple of these are going to the overhead fan in the room. Will a simple clamp meter help me identify the relevant wires?
If by "clamp meter" you mean a non-contact AC Ammeter, and if the circuit can be loaded enough to trigger the reading. Yes, you should be able to isolate the circuit using such a meter. (Keep in mind that this type of meter only registers AC current so you must have current flowing for it to read.)
On a related note, however, that box looks to be severely overloaded. You may want to consider upgrading it as this may be unsafe.
1I have both AC and DC amp clamp meters. As far as tracking by a specific load a clamp can be very handy, I used to use a Holliday light flasher on a large wattage light bulb 150-300w putting my clamp on the line I knew within 1 second if it was the correct circuit, today I use modern electronic tools but this is how I used to trace circuits before the circuit seekers , breaker finders, To tell the truth it was quite accurate . I have had the breaker finders be wrong many times but since there was a pulsing load I never had this method be wrong.– Ed BealJun 10, 2019 at 13:15
@jwh20: By "overloaded" I assume you mean cramped into a small space? It's a real pain, in that the copper wires are incredibly stiff, to the point they barely bend by hand. I am told this is good in terms of safety, but it's otherwise terribly inconvenient for handling.– SabuncuJun 10, 2019 at 15:07
1@Sabuncu Yes, you understand my meaning. It appears that there are too many wires/connections for the volume of that box. But it's hard to tell. Generally if it's difficult to handle, the box is too crowded.– jwh20Jun 10, 2019 at 16:38
@jwh20 Thank you for the clarification. I would love to be able to insert a new and bigger box in there but it requires concrete demolition which generates so much dust.– SabuncuJun 10, 2019 at 16:49