Led signage

[billdozier 78]

Working on installing switches to serve as disconnects for led signage in front of stores. These signs are fed by 120 volt time clocks. The signs are requiring us to turn on and off the switch going to the low volt ballast that feeds the sign. In essence we are bumping the voltage off and then on. Should this be required?

 

[LEO2854]

Working on installing switches to serve as disconnects for led signage in front of stores. These signs are fed by 120 volt time clocks. The signs are requiring us to turn on and off the switch going to the low volt ballast that feeds the sign. In essence we are bumping the voltage off and then on. Should this be required?

Yes you need a disconnect.

From the 2011 NEC..

600.6 Disconnects. Each sign and outline lighting system,
feeder circuit or branch circuit supplying a sign, outline
lighting system, or skeleton tubing shall be controlled by an
externally operable switch or circuit breaker that opens all
ungrounded conductors and controls no other load. The
switch or circuit breaker shall open all ungrounded conductors
simultaneously on multi-wire branch circuits in accordance
with 210.4(B). Signs and outline lighting systems
located within fountains shall have the disconnect located
in accordance with 680.12.
Exception No. 1: A disconnecting means shall not be required
for an exit directional sign located within a building.
Exception No. 2: A disconnecting means shall not be required
for cord-connected signs with an attachment plug.

 

[billdozier 78]

Leo we have the switch serving as the disconnect. The problem is the signs requiring us to manually turn the time clock on then bump the switch. Curious if this is typical of sign ballasts?

 

[GoldDigger]

Leo we have the switch serving as the disconnect. The problem is the signs requiring us to manually turn the time clock on then bump the switch. Curious if this is typical of sign ballasts?

This kind of behavior is required to get a manual override of motion sensor or photocell on some integrated floodlights, but I have not heard of this behavior from a sign.
Is the sign one which has a computer driven or other complicated sequence display? If so the time clock contacts may be bouncing and causing the the sign electronics to go into a state where they will not function without a clean power reset.

 

[tleaf28]

Are these typical 120vac to 12vdc power supplies for LED signs? We mfg and install LED signs and the situation you describe does not sound normal. Our typical install would be when the time clock goes on or off the sign goes on or off. No other sequences are required for turning on the sign. If you are going through a sequence of things to turn a sign on something weird is happening.

FYI, LED power supplies from the good mfgs are basically bullet proof so they are not made with reset switches or restart sequences. We use 20-30 a week and have replaced literally 1 in the last few years. Neon tranformers and fluorescent ballasts are a different story.

 

[GoldDigger]

FYI, LED power supplies from the good mfgs are basically bullet proof so they are not made with reset switches or restart sequences.

What about flashers, sequencers, scrolling text display signs, etc? Those may all have a computer in them somewhere, which makes it a different problem. Or are you saying that you have also worked with those from a good manufacturer and not had problems either?

 

[tleaf28]

What about flashers, sequencers, scrolling text display signs, etc? Those may all have a computer in them somewhere, which makes it a different problem. Or are you saying that you have also worked with those from a good manufacturer and not had problems either?

My understanding is most of those signs are built with junk components as cheaply as possible. I'm not aware of a good mfg of those types of signs. I mainly deal with large signs like channel letters, halo letters, monuments, pylons, etc. Since the OP mentioned a time clock in their original post I assumed they meant a main sign.