PIR sensor drawing large load - safe?

15 Nov 2013
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United Kingdom
Hi all. I have a new PIR sensor (click here to see details and specs, or see http://www.ebay.co.uk/itm/152080948939) which is to replace an existing one of a different type that recently started staying on after several years of service. The PIR sensor is used to switch a 28W wall-mounted light and it comes off of a spur on a socket via an FCU.

I was planning on using a 3A fuse in the FCU (which is also what the existing one used) but when I flipped the switch, the fuse blew.

Is the PIR sensor doing something it shouldn't, or is there a legitimate reason why it would draw more current? I've not been able to find too much information on PIR sensors and fusing, but I've come across a couple of suggestions to use a 10A fuse in the FCU - though reading between the lines that might just be to accommodate the potential maximum load that the PIR sensor can switch. I'm hesitant to use anything higher than 3A because that should already be 25x more than enough for the load.

What do you think?
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Have you wired it correctly? If the fuse blew the PIR may have followed suite (n) if you have shorted LN or L E ? Check for damaged wires in the back box.

Regards, DS
Bin the item. It is extremely poor quality and likely to be dangerous.

Metal front plate and no means to earth it.

Installation instructions are wrong.
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Thanks Nozzle, DS, Bernard - I appreciate it.

I went back and triple-checked the wiring diagrams and sussed it out. On the wiring diagram on the website, they numbered the terminals in the opposite order to the numbers physically printed on the back of the sensor so that they don't correspond :cautious: Terminal 1 on the diagram refers to the terminal labelled "5" on the sensor, and so on. As a result, the neutral+load and load terminals were transposed. After that, I took it to pieces to check the terminals and the earthing - the metal fascia is a thin foil placed on top of a plastic faceplate, with no connection to any metal components inside the unit.

And yes, it was indeed made in China o_O

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