Help with PIR installation problem

[lakelandfolk]

Hi, Just installing a PIR for low voltage LED's in under stairs cupboard but can't get it to work. I have fitted the same PIR in other rooms in the house with no problem but I can not get the required 240 volt supply at the LED driver end of the cable.  When movement is detected, I have 240 volt coming out of the load cable inside  the PIR but at the other end of the cable ( 4metres ) about 23 volts only. I have replaced the PIR with a new one and also the 4m of cable but the same situation exists.

I know it sounds impossible, 240v at one end of a 4m length of 1.5mm cable almost nothing at the other end.

 

Can anyone suggest a possible solution??

 

Many thanks

 

[Jeremy Harris]

It sounds like it has to be a problem with the cable connection at the PIR end, I think.  The 23 V you're measuring is probably a red herring, just induced voltage in a cable that's not terminated.

 

The PIR should have four connections (may only have three, but you'll have to add the fourth for any non-Class II device).  The terminals should be Line In, Line Out, Neutral, and PE (earth).  Often the PE terminal isn't present, but there must be continuity between the CPC on the incoming cable and the CPC on the supply to the LED driver, unless the LED driver is a Class II device, when it's OK to just run 2 core cable and leave the CPC from the incoming supply either terminated at the PIR (if it has a PE terminal) or just cut it back (if the PIR is also Class II).

 

The obvious things to check are that the two line connections in the PIR are the right way around.  No harm will usually result if they are the wrong way around, but the PIR won't normally power up and go through it's initial turn on delay.

 

Other than that, it's a matter of checking the terminals in the PIR to make sure they are actually making contact with the conductor. 

[lakelandfolk]

Hi Jeremy,

Many thanks for your prompt response to my PIR problem. You were spot on with your red herring theory. The PIR was in set up mode and I failed to realise that when activated it would only power the load for about 5 seconds. I was testing the line out voltage with my multi-meter in the PIR which was 240 v but by the time I had come down the ladder and moved to the location of the driver ( in the adjoining room ) the out voltage had been disconnected by the PIR timer hence the odd reading at the end of the cable. I adjusted the cut off timer to 5 minutes and hey presto, 240v at the driver end of the cable. These items, 2 metres of LED Ribbon, a driver and PIR were a car boot sale buy so always some uncertainty and confusion that all were working OK. I do like to recycle but sometimes it can cause problems, this little job finished up taking 3 hours instead of a typical 30 minutes, but all is OK now. The new PIR I purchased has been returned to Toolstation and a full refund received.

Once again, thanks for your help.

Ian