Home automation - consumer unit

[gotti]

I'm currently in the process of renovating my house and planning on adding automation. The initial automation piece will be the lighting circuit. I don't want to buy in a custom instal as I'm planning to add more devices and circuits to this system. I've already coded (some of) the software and designed the hardware circuitry.


My concern are the electrical circuit. The plan is to have an consumer unit (breaker) which will feed on to a relay controlled via an micro controller. I've decided on buying an industrial consumer unit allowing me to mount the relays in but is this acceptable (in the UK) or is it possible to buy in an consumer unit with the relays already built in?

Any advice is really appreciated.


Thanks

 

[Iggifer]

I've decided on buying an industrial consumer unit

What exactly do you mean by 'industrial consumer unit'?

A link to some of the ones you're looking at might help. It's probably fine, so long as you get a suitable model

 

[bernardgreen]

Finder Relay bases type 95.85.3 and similar DIN rail relay bases fit into consumer units with DIN mounting rail . But NOT the type of consumer unit that depend on the bus bar for the bottom fixing of MCBs

Finder_DIN_base

• bernardgreen
• 8 Nov 2015

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• bernardgreen
• 10 Mar 2015
• 4

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• bernardgreen
• 10 Mar 2015
• 3

Indicating LED modules can be fitted in the socket below the relay.
The visible terminals are the ELV control wiring so no a touch hazard if not covered.

 

[gotti]

Hi iggifer,

I've not picked an particular CU but thought a industrial CU with the extra space would allow me to mount the relays. the relays would allow me to switch on/off each circuit. The output from the relays will power a particular room. Do you know a suitable CU that would allow me to mount relays in? Or is there a CU already available?

Thanks

 

[gotti]

Thanks Bernardgreen, do you have any links?

 

[bernardgreen]

Relays

https://www.findernet.com/en/solr_search/series/40/ccid_12:23 ccid_20:129

Sockets

https://www.findernet.com/en/solr_search/series/95

Various suppliers will sell these

There are other manufactures of similar relays and sockets

 

[gotti]

Thanks Bernard. I'm looking to drive the relays from 5V logic level and switch 240V (230-240 coil?) I'll buy a couple of relays and test.


The picture that you've referred to above is that something that you've worked on?

 

[bernardgreen]

Don't drive direct from 5 volt logic. Use the 5 volt logic to drive buffer chips that can switch 12 or 24 volt relays. ULN2803 or similar will give you 8 channels with a 2.7 KΩ load on the logic devices.

http://elcodis.com/parts/6011583/ULN2801_p2.html#datasheet

This provides protection of the logic devices from the back EMF of the relays when they are switched OFF. Fit the ULN2803 in sockets so they can be replaced if damaged by a relay.

Yes it is something I have worked on, it is a slave module to the lighting controller I designed for my cottage.
This controls 10 lamps

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• bernardgreen
• 26 Mar 2015
• 3

The reason I went this route was because running 230 volt cables to switches was not possible as the walls in my cottage are wattle and daub son ELV switching was the only option.

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• bernardgreen
• 31 May 2014
• 5

 

[ericmark]

Personally I would use an adaptable box without really worrying about it. I have been told with domestic we should use type tested gear.

530.3.4 For an installation with a 230 V single-phase supply rated up to 100A that is under the control of ordinary persons. Switchgear and controlgear assemblies shall either comply with BS EN 60439-3 and Regulation 432.1 or be a consumer unit incorporating components and protective devices specified by the manufacturer complying with BS EN 60439-3, including the conditional short-circuit test described in Annex ZA of BS EN 60439-3.

The point is if you can design the system then your not an ordinary person.

But is this acceptable (in the UK)

To whom in the UK, The BS7671 is not law, The LABC inspectors don't seem to be that clued up, So only time your likely to have a problem is rented accommodation in Scotland. You could put it all in an ice cream plastic box and until you get an EICR done nothing would be said.

 

[gotti]

Thanks Guys.

@Bernard - your project looks great! I'm planning on ordering the relays, do I select the 240v coil relays or 6V coils? I'll also order the ULN2803 with the sockets to drive the relays but from your picture above the circuit looks quite complicated.. Any chance of sharing the circuit diagram or guiding me into what else is required..?

Thanks

 

[bernardgreen]

The relays are 12 volt coils so you will need a 12 volt DC power supply as well as the supply fo the processor board you choose.

The board I designed is based on a PIC processor and has 24 inputs and 32 outputs. ( which with hindsight it too few inputs ) and runs a program bespoke to the board. It took about 6 months to get the basic functions and it is still a work in progress with extra functions being added.

It is a complex design with timers and sequencers triggered by inputs to control lights and cominations of lamps as well as basic ON - OFF control of lamps.

It would be best for you to start with something very simple and learn and understand the basic principles of hardware and software before going onto complex systems.

I would suggest something like an Arduino or Raspberry Pi experimental / development board as a starter to learn and develop basic programing skills.

http://playground.arduino.cc/Projects/Ideas is one of many sites with details of how to program Arduino units.

The outputs from the processor board go to the inputs of the ULN 2803 and the outputs of the ULN 2803 go to one side of the relay coil. The other side of the relay coils connect together and connect to the positive of the 12 DC supply. The negative of the 12 volt DC supply connects to the 0 volt of the processor card. The ULN 2803 sockets can be mounted on a piece of strip board ( Vero Board )

 

[ban-all-sheds]

It would be best for you to start with something very simple and learn and understand the basic principles of hardware and software before going onto complex systems.

I would suggest something like an Arduino or Raspberry Pi experimental / development board as a starter to learn and develop basic programing skills.

I've already coded (some of) the software and designed the hardware circuitry.

 

[gotti]

Thanks Bernard..

My current setup consists of a Pi and Arduino.. The controllers are switches/iPhone/iPad. My real concerns were how to connect the circuit to the CU and how to mount my current cheap relays. Now have a better idea on the type of relays i should go for and how to mount them, so thank you.

Last thing - any suggestions on the DC supply.. Should I buy in a transformer or use a DC adapted plugged into the mains?

 

[bernardgreen]

A din rail unit such as the 12 volt version of these

http://www.farnell.com/datasheets/95145.pdf

which is

http://uk.farnell.com/tdk-lambda/dsp10-12/psu-din-rail-12v-0-83a-10w/dp/1456474

will supply 800 mA, enough for 14 relays ( 12 volt, 220 Ω coils ) operated at the same time and fit on the DIN rail next to the relays.

 

[FurstyFerret]

Schneider do a range of home automation / lighting control stuff. Mainly seems to be fitted in hotels to allow multiple points of control but seems ideal for your job.

(Starts on page 135 of their catalogue.)