high bays

[unclebubble]

Recently installed 3 metal halide light fittings in a farm shed.The first 2 on the circuit go from white light to a red light the last on the circuit stays white!The installation is a TT system and I've done a voltage test at the consumer unit and there is 250 v!
Does anyone know with these metal halide light fittings if they need a constant voltage(ie the same steady 230 v)and if a slight voltage drop or surge would keep making these lights go from white to red!
When I left the other day the lights were working fine and stayed working!Any suggestions as no one has come up with anything yet and this is my first dealing with metal halide!Cheers

 

[GaryMo]

Have you tried changing the lamps around to see if the problem moves with the lamp or if it's the fitting itself?
If the problem stays with the fitting then I'd be temped to swap a couple of fittings about.
I've never had that problem though so only suggestions which you may or may not have tried.

 

[RF Lighting]

It sounds like the lamps to me.

Are they all the same make, batch and age?

You'd be amazed at the vairiants in 'white', even with lamps which are supposed to all be the same colour.

When you say red, what do you mean? Is it a bit of a pink tint to he white light, or is it like an intense red, or even orange?

What sort of metal halide lamps are they also? Are they the tubular, eliptical, or double ended type?