Community Forums

Mel rose · 07-23-2020, 07:59 PM

I took down a double dome light fixture from an older camper. I am attempting to install a store bought light fixture 120v. I have bought the needed 12v bulbs. I have tried different fixtures and it works for a second but once i flip the switch it blows the fuse. The ceiling has 2 positive and 2 negative wires coming out where the fixture has once of each. Do I eliminate a set coming out of the ceiling and only use one of each or both. I cant figure out where the problem is. The bulbs are 12v led 2w and the toggle switch is 12v also. Can someone give me thoughts on this

happy2rv · 07-23-2020, 08:19 PM

The two sets of wires are likely because your light fixtures are daisy chained. In other words, power from the switch, assuming there is a wall switch, or power source if there isn't, to the first light fixture (the first set of wires) then to the next light fixture (the second set of wires). These wires should be tied together as they were with the original fixture, positive to positive and negative to negative.

So, without the new fixture attached, are you blowing fuses? Does it work OK if you put the original fixture back up without blowing fuses?

Please provide more information on the new fixture. It is unusual to install a "120V" fixture and install 12V bulbs. How many bulbs does the new fixture have and what type? You indicate they are 2W, but can you provide a model or bulb spec? How many does the old fixture have and what size? What size is the fuse?

You indicate " it works for a second but once i flip the switch it blows the fuse". Does it blow the fuse as soon as you flip the switch? Does it light up at all? 12V DC LEDs are polarized meaning the positive has to be connected to the correct contact on the bulb. If you are using a 120V AC fixture, that would make it difficult to figure out the correct polarity.

Mel rose · 07-23-2020, 08:38 PM

The double dome light had one set of wires going to each side (each bulb) with an on/off switch. The new fixture has one bulb. I read that you can use a house hold fixture as long as the bulb matches the voltage so this is why the 12v bulb. The fuse is a 15.

The new fixture does light up and will stay lit as long as i don’t turn the switch off and back on. If i do it blows the fuse. The old fixture worked fine prior to taking it down.

I wasn’t sure if i connected both sets of ceilings wires to the one set on the fixture being that previously one set went to each side of the dome.

happy2rv · 07-23-2020, 09:04 PM

I'm surprised they were separated on the previous fixture.

I suspect the 12V bulbs aren't "normal" LED bulbs. Many of the 12V edison base bulbs are designed to operate on 12V AC or DC and have additional electronics in them. I suspect there is some type of inrush current when powering up, but I would expect it to be a problem on initial power up as well.

So is the switch integral to the fixture or a wall switch? If it's a wall switch, I would verify that with the wires tied together, but the fixture disconnected, flipping the switch doesn't blow the fuse. I would also try the fixture installed without the bulb. This will verify whether the bulb is the culprit.

Mel rose · 07-23-2020, 10:11 PM

Awesome thanks for some insight. I may be reaching out again tomorrow. I have been tinkering w this light everyday for a week tgen i get frustrated and give up