I have always had trouble with my outside Malibu lights ever since I
moved in 2 years ago. I finally had them working at some semblance of
normalacy last Sunday night. I woke up in the morning and noticed that
the ciruit breaker had switched. Apparently the most troublesome
outside lights (whose bulbs I just changed and i thought were now
working OK) were on the same circuit as a bathroom, laundry room and
several indoor fixtures. I tried resetting but the circuit kept
breaking. Once I unplugged those Malibu lights the rest of the circuit
worked fine. Do you think this is a wiring problem? Do I need an
electrician to sort this out?
If the lights work for a while, and then the breaker blows, it can be a
number of things. The main thing is to check that there are no shorts in any
of the connections, and sockets.
One thing that causes circuit breakers to trip very often is that with age,
it may get too sensitive. The fix is to replace the breaker. Another thing
that causes breakers to trip, is that there are too many things plugged in
to the same circuit, and the breaker is going what it is supposed to do.
If you are not used to dealing with this type of electrical work, you would
be safer off to get a professional electrician to service your problem for
Check the breaker that trips. Is it a GFCI breaker? (Ground Fault
Circuit Interupter). Does it have a "test" switch? It sounds like it
might be if it also connected to the bathroom outlets. If so, it's
just doing its job to protect people from getting electrocuted on your
It could be tripping because of a ground leakage fault in the Malibu
Lights. Most likely this is occuring in the transformer that steps
down the 120V to 12 volts or so for the lights. Unplug and check the
continuity with a meter, if you can. There should be close to
infinite resistance at the plug between hot and ground and neutral and
ground. Are you getting a reading other than infinity? Then the
transformer ground leakage fault is causing your problem.
This may not necessarily be dangerous. Leakage currents are common on
GFCI outdoor circuits. They often cause a condition call nuisance
tripping when used with a GFCI. They might occur when the downstream
outlets are damp. Often it is difficult to track down the exact
source of the problem but I'd put my money on your Malibu Light
Unless the GFCI is faulty, having a GFCI trip because of a LV
lighting system means that something is definately wrong with the
Even if the LV wiring was short circuited/grounded et. al., the GFCI
upstream of the transformer will _not_ trip. For a LV fault to
trip the GFCI, the transformer would have to have to be faulty too.
It's more likely that it's the outlet or high voltage side of the
For the GFCI to trip, there must be a leakage current from the neutral
or hot to ground. If the transformer is okay, this can only happen on
the high voltage side of the transformer, or in the outlet it's connected to.
I'd _tend_ to suggest that the hot side of the transformer or the
transformer itself is getting damp, and a conductive path is present
to ground. Possibly through the transformer frame. Alternately,
the transformer has a coil-case short, and moisture is providing
Alternately, the outlet itself is damp/corroded or gunked up and
the transformer is providing the hot-ground path.
Disconnect the unit, bring it indoors, let it dry out thoroughly
and clean it. Especially crud around the plug, or where the
wires enter the transformer. If the transformer unit is easily
opennable (not a plastic molded case), open it up and clean it.
With the power _off_, open up the outlet, check for moisture,
corrosion or debris (particularly bug bits). Clean out and dry.
Make sure you reassemble the seals properly.
When you put the transformer back outside, try to shelter it from
weather, but don't seal it completely, because that will lead
Then see what happens. If it still trips, I think you need a new
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
* outside Malibu lights
* same circuit as a bathroom, laundry room
* tried resetting but the circuit kept breaking.
All that adds up to one thing. You have a GFI and it is detecting a
I would guess if you have a week or two of dry weather, the problems
would disappear until you got a good rain.
Start checking all outside outlets including the one powering those
lights. I suspect you will find that one has some sort of leak allowing
water in. Fix that and you should be OK. It is still possible the
breaker - GFI is bad, but in this case my money is on a real ground fault.
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