I have this transformer for the ceiling lights (about 7) on my boat and start blowing the 10amp fuse on the 24v side. I changed the transformer, checked all the connections at every fixture, I tried to switch the transformer to the other side lights and the problem switched side as well.
Could it be the fuse holder that has bad contact? What else could it be?

Sounds like an overload... what is the wattage of the seven fixtures you have connected?

sounds like an overload....what is the wattage of the seven fixtures you have connected?

Those are 20watts. I do have 2sets like that, one transformer for each side of the walkway ceiling. After switching them one side to the other, its still the same transformer that blow the fuse. No problem at all with the other one.

Those are 20watts. I do have 2sets like that, one transformer for each side of the walkway ceiling. After switching them one side to the other, its still the same transformer that blow the fuse. No problem at all with the other one.
Its actually 110/12v transformer

So you have seven fixtures at 20 watts each on a 12 Volt, 10 amp fuse..
7 x 20 = 140 watts... 140 watts / 12 = 11.6 amperes...
The math says that you have too much load on that circuit...
What size and type of conductors are installed? If the conductors are large enough then
a 12 amp fuse may solve your problem.

Its 12gage and not sure of the type of wire. I changed the fuse holder for a better quality one and found a bit of wire that was 14 gage so switched with 12 gage and installed. 15 amps fuse. Seems to be holding fine now, will see in a couple hours.
Thanks for the tips, hopefully it will stay on this time.
So you have seven fixtures at 20 watts each on a 12 Volt, 10 amp fuse....?
7 x 20 = 140 watts.....140 watts / 12 = 11.6 amperes....
The math says that you have too much load on that circuit...
What size and type of conductors are installed? If the conductors are large enough then
a 12 amp fuse may solve your problem.