Power Surge when I turn Controller on

[EmmienLightFan]

Everytime I unplug or plug in my CTB16PC, the fuse bulbs in any lights connected flash really quickly and really bright (So bright that it is like one of those cartoon star flashes). The fuse bulbs become blacker and blacker, but never go.

 

I am running at 220v, btw.

It doesn't really matter. I worried that the fuse bulbs will go or it will damage my LED set or something.

[LOR Staff]

I have no idea what a fuse bulb is, however:

 

That would be the normal functioning of a Triac based controller of any kind at any voltage.  Triacs require that there be voltage behind the gate in order to shut the current flow off.  When there is no voltage behind the gate, the gate is usually open (or more correctly 'floating').  

 

You plug the controller in, current flows through the triac since it is floating open.  After a few cycles the voltage has built high enough to force the gate closed.

[EmmienLightFan]

Oh. I understand it now. Thanks very much!

 

A fuse bulb is only found in the UK.

All Incans must have one at the start of each string. They go very quickly, so if there is a fault we have an extra layer of protection. It is strange that you don't have one, especially considering you don't have fused plugs either!

Edited March 30, 2015 by EmmienLightFan

[LOR Staff]

Actually, Incan Portable/Temporary light sets here in the USA have been fused for several years now.  Initially it was only higher amperage sets (like C7/C9), but was soon extended to even Mini light sets.  Both legs are fused at 3A

 

I do not know what the requirements are for LED sets and/or sets that can not be connected end-to-end.

[Mega Arch]

All new strings have fuses.

Most of ours have fused plugs.

The balance have an enclosed fuse holder.

Main safeguard is LOR has built in fusing as well.

[Alan C]

Light sets sold in the UK have a "shorting wire" in each lamp except the "fuse lamp". The idea is that when a lamp fails, the shorting wire shorts out that lamp, such that one lamp goes out rather than the entire set. When a lamp is shorted, the voltage normally across it is divided amongst the rest of the set, making the remaining lamps brighter. If too many lamps fail before the user replaces them, the "fuse lamp" will fail, but as this does not have a "shorting wire" in it, the entire set goes out rather than catching fire. These "fuse lamps" normally have at least part of the glass painted white, so that they can be easily recognised and are often found at the start of the string.

 

Regards,

 

Alan.

Edited March 30, 2015 by Alan C

[Darryl Lambert]

They have something similar to your "shorting wire" here in our minilights. It's called a "shunt" Same sort of idea when the bulb burns out the shunt is suppose to let the power flow through that bulb so the rest will remain lit. Only it sounds like a good idea but half the time it doesn't work & the string goes dark.

[EmmienLightFan]

Ours work every time

I never knew your lights had fuses. Where are they? Are they just inline fuse holders on the wire?

 

Also, if anything you need more protection than us, as you can use incans outside. We can only have LEDs outside (Few exceptions such as low voltage incans) and a cheap LED string costs £10, and that is normally the ones without the transformer.

[Steven]

Ours work every time

The shunt has a layer of non-conducting oxide between it and the filament wires. It activates when the voltage rises high enough to break through this oxide. A typical light is about 2.5v, but when it blows, the voltage rises to the mains voltage (120v). This is usually enough to break through the oxide, but 220v would be more certain.

 

I never knew your lights had fuses. Where are they? Are they just inline fuse holders on the wire?

 

Here's a picture of the plug at the end of a typical light string, with the fuse door open, and one fuse removed: