Wiring an Electrical Timer/Possibly "Volt-Free Output&q

[Mineral]

Hey guys,
I'm in the process of trying to wire up two lighting systems for my reptile tank with a timer to switch them on and off as needed throughout the day.

The first lighting system (Load A) runs through a 240vAC > 12vDC LED Driver which is then connected to a pair of red LED strips via a choc block.

The second lighting system (Load B) runs through an in-line 240vAC > 54vDC (no idea why it wants so high a voltage) transformer to an enclosed strip of white LEDs.

The timer is a TM-812M-2 twin channel digital programmable timer switch that I got from Amazon.*

A plug was wired to the timer to provide it with a 240vAC input. Looking at the instruction sheet** for reference, the live wire has been connected to terminal 4. The neutral wire has been connected to terminal 5.

Load A has been connected to Channel A; the live wire to terminal 1 (Channel A: Normally Open) and the neutral wire to terminal 2 (Channel A: Common).

Load B has been connected to Channel B; the live wire to terminal 6 (Channel B: Normally Open) and the neutral wire to terminal 7 (Channel B: Common).

Now, my problem. I can confirm continuity between the various terminals is working as intended - when Channel A is switched 'On', there is continuity between terminals 1 and 2, and continuity between 2 and 3 when switched 'Off'. However, none of the connected equipment operates, and checking for voltage shows there is no voltage running through any of the output terminals.

I studied the leaflet again and found a sentence that I believe explains this; "This Timer provides Volt-Free output contact only." - I've googled Volt-Free output but don't really understand it, nor have I been able to find a guide for using it. Is this what the issue is? How do I get around it?

* http://www.amazon.co.uk/dp/B0077AX0US/ref=pe_385721_37038051_pe_217191_31005151_3p_M3T1_dp_1

** http://www.king-ielec.com.tw/all/manuals/timer/619mode_812m.pdf

 

[Mineral]

Well, I'm a dumbass. Worked out that I needed to provide my own voltage via the actual "output" terminals and the "input" is only needed to actually power the switch.

 

[EFLImpudence]

Volt-free just means A an B are not connected to 4 and 5.
You can connect any other voltage through them.

If I understand correctly - You say
"Load A has been connected to Channel A; the live wire to terminal 1 (Channel A: Normally Open) and the neutral wire to terminal 2 (Channel A: Common)."

According to that you have not connected the 12V supply.
The neutrals should not be connected to the timer but just connected together.
Terminal 1 - 12V supply from transformer.
Terminal 2 - Switched 12V to the load (light)

Same for B.

Draw it and you will see why it doesn't work.

 

[EFLImpudence]

Well, I'm a dumbass. Worked out that I needed to provide my own voltage via the actual "output" terminals and the "input" is only needed to actually power the switch.

Ah. Eureka.

Now you know why it's called volt-free.

 

[JohnW2]

Now you know why it's called volt-free.

That would be because it is free of volts until you connect some to it

Kind Regards, John

 

[Mineral]

Well, I'm a dumbass. Worked out that I needed to provide my own voltage via the actual "output" terminals and the "input" is only needed to actually power the switch.

Ah. Eureka.

Now you know why it's called volt-free.

Actually a really clever idea now I understand it - since I'm going to be running all three devices with the same input voltage (the timer, LED driver and transformer) I'm just going to piggyback the inputs from 4 and 5 to both of the channels.

I vaguely remember opening a PID unit a couple of years back that I believe was wired in the same way. No danger in doing this, is there?

Gotta love those Eureka moments!

 

[Mineral]

There we go, I've wired channel A in with the 'input' terminals, as well as the connection to the actual LED driver.

Untitled

• Mineral
• 16 Aug 2013
• 1

Danger of death out of 10?

 

[EFLImpudence]

WAIT.

You have not done it properly.

Which terminals are which?

All Neutrals should be together in the same terminal.

 

[Mineral]

WAIT.

You have not done it properly.

Which terminals are which?

All Neutrals should be together in the same terminal.

Cheers, EFL! How about this? Have I interpreted you correctly?

Untitled

• Mineral
• 16 Aug 2013
• 1

Left to Right:
1 2 3 4 5

2 = Channel A COM (LED Driver)
3 = Channel A NC (LED Driver)
4 = 240vAC Live
5 = 240vAC Neutral

 

[EFLImpudence]

No you need to use the NO terminal '1' for the link.

If the white cable is 240V supply.

I wasn't sure, that's why I edited my post.

 

[Mineral]

No you need to use the NO terminal '1' for the link.

If the white cable is 240V supply.

I wasn't sure, that's why I edited my post.

Thanks, EFL. And again for the patience - I've not worked with anything beyond a simple in-line switch before this!

Got my diagrams drawn up and feel confident that nothing is going to explode in my face. Time to break out the choc blocks!

 

[OwainDIYer]

Wire as shown:

View media item 65181
Dotted lines are switched lives.

CPC (earth) omitted for clarity.

The timer to be mounted in an appropriate enclosure and strain relief glands provided for the cables.

 

[EFLImpudence]

Whilst correct, I feel you may be introducing confusion by swapping the connections, not to mention the blue 'loops'.

 

[Mineral]

Think I've managed it, wired everything into a project box to test it before I go installing it inside the reptile's cabinet.

I've got the neutrals from both lighting systems going to a choc block which connects them directly to the plug's neutral prong, with the lives going through the timer (with both A and B getting their 240vAC live from terminal 4).

Going to test it out with nothing connected and my multimeter to make sure there are no unexpected electrical fires!

 

[Mineral]

All done and functioning perfectly with no abnormalities! Time for a tidy up and a well-earned break, I think. Have just popped the project box into the cabinet for the time being - will hopefully be mounting the system properly tomorrow.

Thank you to everyone who replied to the thread!