Ask The Trades - Print Page

Ask The Trades
https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Electrical Questions >> External LED's. Which side of Transformer for PIR? https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1399204338 Message started by Mick01329 on May 4^th, 2014, 12:52pm

Title: External LED's. Which side of Transformer for PIR?
Post by Mick01329 on May 4^th, 2014, 12:52pm

Hi
Am looking to fit some external LED strips to a covered way, and control them via PIR, with 230v/12v transformer mounted internally.
Question is, should PIR be on primary or secondary of the transformer? I am only using 5mtr of strip, so looking at 100W max, which appears to be within the spec of many PIR's (using 100W inductive load rating). If I can, I'd prefer to switch primary side and not to have transformer operating unnecessarily.
Cheers

Title: Re: External LED's. Which side of Transformer for PIR?
Post by Lectrician on May 4^th, 2014, 10:08pm

You should always switch the primary.

Title: Re: External LED's. Which side of Transformer for PIR?
Post by Mick01329 on May 4^th, 2014, 10:13pm

Lectrician

Thanks for reply - certainly makes most sense.