DIN rail Terminal Blocks - home automation - best layout?

a546345 · 21 Nov 2019

Thinking about using these for my next automation project. Wondering what the best layout would be?

Up until now I have ABS enclosures dotted around the house.

Each enclosure would typically have one or more RCD/RCBO protected sources (eg. lighting radial, power) along with their Neutrals and earths, maybe a 12V supply, an 8 way relay board, and then cables going to each destination eg. lights.

I typically bring the sources to a screw terminal block section, then the appliances to another terminal block section, and then wire the relay terminals between the blocks. This is time consuming, difficult to change, and not always very neat.

What would be the best way of doing this with DIN rail terminal blocks? All sources (Live, Neutral, Earth, Live, Neutral, Earth etc,) into one section on the rail, relays to the next section, and destinations to the next section, with jumper blocks?

Or Source Live, Relay Live, Relay Switched, Destination Live, then same for neutrals? Or using 3 layer terminal blocks with live, neutral, earth coming into each slice?

Thanks.

bernardgreen · 21 Nov 2019

For what it it worth this is one of two relay modules that control the lighting in my cottage. The enclosure is a plastic enclosure that was once sold as a consumer unti but nowe can only be sold as an "enclosure" for equipment.

All lights are wired back to the control module and terminated on a DIN added to the enclosure. Relays are fitted in socket fitted to te DIN rail that would in a consumer normally have MCBs fitted to it.

Most of the relays are group in sets of three controlling two lamps. Dimming is by connecting a pair of lamps in series.

a546345 · 21 Nov 2019

Thanks Bernard, can I ask which DIN relay holders, and relays you're using please? Can they be driven directly from an Arudino output, or does it need an outboard transistor drive? The relays and holders I've seen from RS/Farnell are more expensive than your typical 8 way Songle relay board, but would give me more comfort that they are properly designed to take mains current and voltage.

On the left-hand-most relay, what is the yellow jumper-like pin?

bernardgreen · 22 Nov 2019

The relays are Finder 40.31.7.012.0000 12 volt DC Singe Pole Change Over
The sockets are Finder 95.83.3
The relays are driven by ULN2803A octal drivers
The control;er is a self designed processor board using PIC2620 processor with 32 opto coupled inputs and 32 relay driver outputs.
The yellow jumper like pin is a poor image of the Yellow/Green Earthing connector on the DIN rail.

The separation of mains from ELV coil in the relays and sockets exceeds what is necessary for safe isolation.

As for pricing, I buy Finder items from HERE

SimonH2 · 24 Nov 2019

I would be inclined to have a set of connection terminals to which you bring the outgoing cables. To save a bit of wiring, you can group the neutrals and earths - the earths are commoned by being clamped to the DIN rail, the neutral blocks can be commoned with jumper bars.
Then on either the same or a different DIN rail - or even on board mounted in the enclosure - have your relays. You can then assign relays to lights by fitting a jumper from relay terminal to output terminal, and regrouping lights is just a matter of changing the jumpers.
And if you decide to go with (for example) DMX or DALI switches/dimmers, you can simply replace the relays with whatever modules you decide on and re-jumper accordingly.

bernardgreen · 25 Nov 2019

SimonH2 said:
To save a bit of wiring, you can group the neutrals and earths

This can result in a "spagetti" of the Neutrals and Earths from the twin and Earth cables, Putting the L N and E from a cable in adjacent connectors then linking the Neutrals with a wire makes it easier to wire the DIN rail connectors. Earth connectors are linked by the DIN rail

SimonH2 said:
You can then assign relays to lights by fitting a jumper from relay terminal to output terminal,

or change the configuration in software which means the wiring of relays and DIN rail connectors does not ( should not ) need to be changed in the future.

Simon35 · 25 Nov 2019

bernardgreen said:
This can result in a "spagetti" of the Neutrals and Earths from the twin and Earth cables, Putting the L N and E from a cable in adjacent connectors then linking the Neutrals with a wire makes it easier to wire the DIN rail connectors. Earth connectors are linked by the DIN rail

or change the configuration in software which means the wiring of relays and DIN rail connectors does not ( should not ) need to be changed in the future.

Got to agree with Bernard here, I always get control panels manufactured with a block of consecutive terminals per cable. Having said that they would also have a trunking for the incoming cable to arrive into between glanding and terminal rail, so any spaghetti is hidden.

bernardgreen · 26 Nov 2019

Simon35 said:
so any spaghetti is hidden.

Evenually the spagetti between floor and enclosure will be hidden.

a546345 · 16 Sep 2020

Thank you all for the inspiration. Here's what I ended up doing for the lighting in the new extension. All switches and feeds to lights home runned into the box. Zwave or relays, or other dimmers to go on the upper DIN rail eventually.

Simon35 · 16 Sep 2020

a546345 said:
Thank you all for the inspiration. Here's what I ended up doing for the lighting in the new extension. All switches and feeds to lights home runned into the box. Zwave or relays, or other dimmers to go on the upper DIN rail eventually.

View attachment 204932

I'm sure it works, but it ain't pretty

Why no trunking for the wiring above the terminal rail, does it have any mechanical support?

Why does the black wiring below the terminal rail go off horizontally to enter the trunking?

mattylad · 16 Sep 2020

I see no end stops being used.
Without them your terminals can wander.

You also need end covers on them if your going to have a gap, I can see metal on the right edge of the leftmost group - the same will be on the other groups - this can allow you to touch a live terminal.

Using the earth terminals can achieve the objective of both of these although it will split them up from the single group of earths.

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DIN rail Terminal Blocks - home automation - best layout?

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