Can Anyone "shed some light.."

how did you verify the volts at each bollard ?,  -I am  thinking that a modern high impedance meter can read voltages that fall away to zero in the presence of any real load - do you have one of those bayonet to meter pins adapters ? - then you can buzz it on ohms with it off, to verify low impedance connections. This picture is the screw in kind but bayonet ones also exist - it may be that there is something not quite making contact behind the lamp holders

Also your  comment about current implies something odd, I'd expect the working  lamp to draw a lot more than the ones not lighting !! perhaps you can describe how that was tested as well.

Mike

Hi mapj1,

a Two prong tester with the built-in Current Jaws used throughout, (the Fluke T5-600 or equivalent) for the BC pins

(not a great measurement on the Amps was taken, tbh, but from memory was around an amp) they're little LED lamps.

an amp sounds an awful lot for an LED in a bayonet fitting, I'd expect no more than a few tens of watts, perhaps of order 0.1 amps

Mind you looking at the spec for that meter, the input impedance is not the highest - about 1 megohm, and the amp range, at 100 amps full scale could be a few hundred mA off, so the meter may be in spec, and at the same time misleading.

Mike.

Asking the silly questions first, the bollards don't have a built-in photocell or other controls do they?

   - Andy.

Hi Andy,

- No inline controls, sneaky photocells on bollards or side of the building etc. They are switched through this time clock though and that crossed my mind, as a possible compatibility issue.

Mike I have to pop back to swap a light elsewhere on the building (unrelated) and can re-measure the Amps, the but as you said at a couple of Watts per lamp (maybe 13watt each?) I'm at the low end of the testers tolerances.

maybe I should re-wire all the gubbins in 10mm Al singles      

How about (temporarily) connecting individual bollards using a length of flex, with a 13A plug attached plugged into a looong extension lead?

If the bollard lights on the temporary connection then at least you have a starting point - you know the bollard is good so it must be a supply issue.

Try a different light or temporary lamp holder to the supply of one of the bollards. Also I had an incident once where the part of the lamp holder that holds the lamp in place wasn't correctly lined up with the pins so they were not making contact . I have also had times when the contacts on the back of the lamps don't reach a pin or pins but sounds unlikely on several fittings. I would definitely try a temporary light first to eliminate a supply issue.

Gary