Wiring a contactor

thomP · 11 Nov 2009

I haven't wired a contactor before (this is a 2-pole Square D CCN225) and would appreciate any views and advice on the following:

I have a 5.5KW heater that I'd like to control via a timer. I'm proposing to use a standard plug in timer to power the coil on the contactor (I'm assuming A1 is live and A2 is neutral for this - I have no wiring diagram)

The contactor then has 4 terminals (1,3 on top of contactor and 2,4 at bottom) - again with no wiring diagram I'm assuming that 1,3 will be wired live/neutral from power source and 2,4 will be wired live/neutral to the heater.

Does this sound ok, is there a better alternative?

thanks

Tom

Spark123 · 11 Nov 2009

There is usually some sort of schematic on the actual device, A1 and A2 are for the coil and the contacts are between the top and bottom as you say.
Not sure on the concept of wiring it up to a plugtop, I'd prefer to use a fixed timer.

thomP · 11 Nov 2009

Yes there is a schematic though not particularly detailed for a first time user, where I was a little unsure was the 4 terminals but as it's a 2-pole I assume that it switches live and neutral hence 1,3 and 2,4 will be wired live/neutral.

I agree with what you say about the fixed timer but I have a plugtop that I can use, keeps it more cost effective - would there be any obvious safety issue with this or is it just that a fixed timer is a cleaner solution with fewer parts to go wrong?

Collectors · 11 Nov 2009

This might be similar? Just make sure the contactor coils is 220/240 volt.

thomP · 11 Nov 2009

Thanks - a picture paints a thousand words - that really helps.

T

Aragorn84 · 11 Nov 2009

I guess it doesnt matter much, but wouldnt the "in" normally be at the bottom?

bernardgreen · 11 Nov 2009

It might be more likely to work if the cables are fitted in the connections labelled with 1, 2, 3 and 4 next the the ones marked by the arrows.

There may be terminals in the un-marked holes but they may not be connected to switch contacts. ( they would be if it was a 4 pole contactor )

bernardgreen · 11 Nov 2009

Aragorn84 said:
I guess it doesnt matter much, but wouldnt the "in" normally be at the bottom?

Given a free choice I would put IN at the top so that in the unlikely event of a screw coming loose and the wire dropping out of a bottom terminal that wire will not be a Live feed.

333rocky333 · 11 Nov 2009

Is the heater on the same circuit as the socket.

If not a warning "Isolate all supplys " label, or similar may be wise on the enclosure.

Aragorn84 · 11 Nov 2009

bernard: Ye i guess, i was just considering that most CU's that use the din rail arrangement have the live rail at the bottom?

333rocky333 · 11 Nov 2009

They dont usually go on the cu busbar as that is normally Live only.

I always thought that, Looking at the diagram on the contactor above, the line with the switch bit leaning to the left is usually the output, and the straight line is the input.
Not that it matters on that contacter

Aragorn84 · 11 Nov 2009

It might matter depending how the "ON" light is wired?

I would have thaught the moving part would be connected to the source looking at the diagram?

http://4x4icon.com/offroad/headlight_warning/relay_diagram.gif

Compare it with that for instance, "30" is battery live. Most relay diagrams are the same, moving contact is the feed.

matt1e · 12 Nov 2009

Collectors said:
This might be similar? Just make sure the contactor coils is 220/240 volt.

Spot the mistake(s)

VanSolo · 12 Nov 2009

Would be best to use the terminals with contacts in them.

matt1e · 12 Nov 2009

VanSolo said:
Would be best to use the terminals with contacts in them.

It would indeed Van

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Wiring a contactor

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