Since I've wired most of my cages and my house for that
matter, I tend to lean more toward a circuit or electrical
problem. If It were me I would begin with the electrical
panel and work my way through the plug circuit which
ends up lighting the cages in question.
1) Check the electrical service panel make and sure that
the breaker doesn't have too many separate lines
(individual circuits going to different rooms, appliances etc)
on that circuit breaker which powers the problem cages.
If so, have someone who is experienced/qualified either
move all or some of those extra lines to other breakers or
add a new breaker and only connect the wires leading to
the room in which the cages are plugged in at.
2) You can purchase a cheap multi meter which will read
various voltages at 120v, 240v as well as dc voltages. A
digital meter will be more accurate but a cheaper dial meter
will work just fine. Set the meter to 120 vac and plug the
test leads into the wall outlet so you can monitor any voltage
highs or lows and even voltage spikes etc.
Be sure that the outlets you are using for the cages are not
overloaded with other appliances. I usually use an outlet strip
then plug the cage cords into it for additional protection from
surges etc.
3) Check the cords from the lamp sockets to the to the cord
plug. Make sure it is a good quality (UL approved) and is at
least a 14-3 size cord which should be in good shape and not
frail at any point.
4) For ceiling mounted lighting, be sure to use a UL approved
ceramic or porcelain lighting socket which are rated for the
lamps used and make sure the wires are hooked up properly
on to the color coded screws (hot/brass, neutral/silver,
green/ground). I always use a galvanized lighting octagon ext
box then mount the porcelain socket to it which allows a couple
of inches of space between the socket and the cage ceiling. Use
the proper size reflector domes (for the size of lamps used) so
that the lamps wont overheat.When using the 'clamp light fixtures' make sure the sockets are also porcelain or ceramic and rated for the lamp wattage used.
John