Wiring a switch timer

timer

I’ve bought this timer: http://www.pdlglobal.com/data/product_documents/784_installation_guide_document.pdf

The wiring diagram is in that PDF.

I need help understanding how to wire this up. I’m replacing an existing switch, so there are two phase wires (red), two neutral wires (black) and two ground wires (green/yellow) in the wall. I know which phase wire is live.

I tried wiring it up with the live going to 2, phase output going to 1 and each neutral going to 3 and 4 but that caused the fuse to trip which means it was a short circuit.

I then tested with a non-mains power circuit and found 3 and 4 are the “switch” so I connected the live to 3 and the other phase to 4 and that’s working as a switch but the timer isn’t counting (the neutrals are looped with a cable joiner but not connected to the timer). I now realise this is happening because the timer needs a neutral to complete its own circuit to run the counter.

Advice on this would be really appreciated!

Best Answer

Attach a red pigtail to terminals 2 and 3.

Splice source red, pigtail 2, and pigtail 3.

Land load red on terminal 4.

Attach a black pigtail to terminal 1.

Splice source black, load black, and pigtail 1.

Edit:

Note that with this electrical system the hot is red and the neutral is black, not the US color code system.

If you wire this otherwise you can have all kinds of unintended results. If you connect the switch in series with the load in series with the timer, with the timer initially in the "on" interval, it could run until the timer advances to the off position, then both the switch and the timer will turn off. One way to get this odd result would be to wire constant hot / live to 3, NO (4) to load neutral, load hot to terminal 1, and terminal 2 to neutral.

Other hilarity could ensue if you connect the source hot / constant hot to the NO (4) or NC (5).

Since switching neutrals is generally avoided, the neutral should be connected to terminal 2 and no other terminal on the timer switch.

My thoughts would be to very carefully examine the terminal markings and make sure I have identified them correctly, then test the device thoroughly. Also, double check that you have correctly identified the source hot and load hot.

The next test, which the OP has conducted, is to see if the timer runs with source hot to 2 and source neutral to 1. I'd do this again, after double checking the terminal IDs and the source hot.

Next I'd bench test the switch. The instructions don't spell this out explicitly but this is what I'd expect to see assuming it's a typical timer.

With the switch totally disconnected on the workbench, hand turn the timer into the "on" interval you should see

  • Continuity - high resistance between 1 & 2
  • Continuity - zero resistance between 3 & 4
  • No continuity between any other contacts

then hand turn it into the "off" interval and you should see almost the same thing...

  • Continuity - high resistance between 1 & 2
  • Continuity - zero resistance between 3 & 5
  • No continuity between any other contacts

If it passes those tests, and it doesn't operate properly,

Related Topic