Jump to content

Fuse Protection


Duke
 Share

Recommended Posts

I have some strings of lights that are older and do not have the mini fuses in the plug. If I were to use these with LOR, will the fuse in the controller be enough protection in the event of a short on a single channel?

Link to comment
Share on other sites

I think that might be a Dan the Man question, but I think the fuse is protecting against over-current only. I don't think the fuse was for that type of protection.
You should get new lights!
Hope this is a help to you.
Have a great day!
Don

Link to comment
Share on other sites

Here are my thoughts, and this is just a partial answer. If you have the PC controllers, their fuse will allow around 5 times as much current as the typical 3A fuse in the mini lights. To me this implies that any fire hazard event can be 5 times higher before the fuse blows.. Of course, this is not the full story, because I believe the 3A fuse is sized so that it will blow before the light string wiring gets too hot. You could probably pull 14A thorough that 15A fuse for weeks on end, but I think the insulation on the light wiring would go up in flame in a fairly short time at 14A..

- Kevin

Link to comment
Share on other sites

klb is pretty much right on. Also if you had a short and your were connected to a GFCI which is strongly suggested then that would be your safety net because it would trip if their ever was a short in your christmas lights. Of course that short would have to come in connect with mositure or ground for this to happen I beleive. In an overload sitution of your christmas lights it would not blow the fuse in your controller because of the facts klb already stated. The fuse in the contollers are protected the load of the controller and until the peak is met which is 15 amps then it would not blow it. Your Christmas Lights would burn up before it would blow the fuse. Keep in mind though depending on the short it might trip the GFCI first. I would just replace the lights that are not fuse protected.

Link to comment
Share on other sites

The reason all mini lights have fuses in the plugs is not primarily to protect against an accidental short, but to protect against multiple lights burning out.

When a mini light burns out, the higher voltage across the burned-out filament will cause the built-in shunt to short, which keeps the rest of the lights in the string burning, so you can easily identify the bad bulb. However, when this happens the rest of the bulbs in the set have a slightly higher voltage across them (2.45volts instead of 2.4 volts). This is not a problem when you just have one or two bulbs out, but if the string is neglected, and 5 bulbs burn out, now you have 2.67 volts. This is more than the 2.5 volts at which the lights are rated, so now they will start to burn out faster.

Eventually, when enough lights burn out, the 3A fuse in the plug will blow, protecting the wire and sockets.

Without the fuse, the current through the wire will probably rise enough to overheat it, catching fire, and thus break, protecting the 15A fuse in the controller. :)

This is only the worst-case scenario. More likely will be that you will notice multiple bulbs out and replace them.

Link to comment
Share on other sites

Thanks all! Old lights... poop... K'chunk into the circular file! That makes sense. I am going to be making 5 tri-color (RWG) 7 segment arches for this years display and I'm thinking of incorporating the controllers (1 16ch & 1 8ch) for each into the bases/ends of each arch. Since these will be custom enclosures, I will also incorporate 3 amp fuses on each channels hot output rather than keeping the bulky plug fuse combo. I plan on using two 12 pin male/female connectors and a single pin for a common neutral to simplify and condense the hookup. The com cable and 120v supply to the next controller in line, will run internally through the arch. My end goal for setup would be as follows:

1. Position and anchor the bases/controllers to ground.
2. Insert and lock arches into bases.
3. Plug in 2 multi pin and common neutral connectors, com cable and 120v to base.
4. Get a beer and test.

Also, all these will be run off one 15amp circuit since they'll be 100% LED.

Now where's those LED's from Paul........

Although flaming arches would be unique now wouldn't they? JK!

Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
 Share

×
×
  • Create New...