24v DC Relay Wiring

[russ9898]

Hi guys,

Got a job to wire some new emergency lights in a residential home we look after.

Currently the entire buildings emergency lights are supplied by a 24v DC central battery system. The system also has a timer installed to switch the lights on at night to provide night lighting for the elderly residents as the main communal lighting is PIR opperated so takes a second or two for the fluorescents to kick in.

There were additional lights installed on the battery system a few years back and no one took volt drop into consideration. Its been drawn to our attention that these fittings are blowing lamps within days of being fitted. After measuring the voltage at these fittings there is only 18v ish.

To rectify this we are replacing the lights with 230v AC 8w maintained bulk heads. There is a 230v permanent live and neutral available at the 230v fluorescent fittings next to the 24v dc fittings which we can use for the new 230v emergency fittings charge circuit.

What i dont have is a 230v switched supply to switch the fitting on at night as a night light. So ive come up with the idea of using a 24v dc relay to create a switched supply. So when the battery unit switches its 24v supply on for the night lights, the relay will drag in and switch the 230v maintained side of the emergency fitting.

Now im fairly recently qualified and not afraid to admit when im not 100% sure on what im doing in terms of wiring the relay.

Would anyone be so kind as to explain to me what pins i need to connect my

A) 24v DC Switched supply (From Central battery unit)

B) 230v Permanent Supply

C) 230v Switched Supply (Switched via relay)

I have an 8pin relay and base.

Thanks alot,

Russ

 

[Lee321]

Hi guys,Got a job to wire some new emergency lights in a residential home we look after.

Currently the entire buildings emergency lights are supplied by a 24v DC central battery system. The system also has a timer installed to switch the lights on at night to provide night lighting for the elderly residents as the main communal lighting is PIR opperated so takes a second or two for the fluorescents to kick in.

There were additional lights installed on the battery system a few years back and no one took volt drop into consideration. Its been drawn to our attention that these fittings are blowing lamps within days of being fitted. After measuring the voltage at these fittings there is only 18v ish.

To rectify this we are replacing the lights with 230v AC 8w maintained bulk heads. There is a 230v permanent live and neutral available at the 230v fluorescent fittings next to the 24v dc fittings which we can use for the new 230v emergency fittings charge circuit.

What i dont have is a 230v switched supply to switch the fitting on at night as a night light. So ive come up with the idea of using a 24v dc relay to create a switched supply. So when the battery unit switches its 24v supply on for the night lights, the relay will drag in and switch the 230v maintained side of the emergency fitting.

Now im fairly recently qualified and not afraid to admit when im not 100% sure on what im doing in terms of wiring the relay.

Would anyone be so kind as to explain to me what pins i need to connect my

A) 24v DC Switched supply (From Central battery unit)

B) 230v Permanent Supply

C) 230v Switched Supply (Switched via relay)

I have an 8pin relay and base.

Thanks alot,

Russ

need to see the relay and base configuration

you have got a 24v relay rated to 240v?

 

[oldtimespark]

What make is the relay? If it follow the standard octal base configuration the connection diagram is normally printed on the plastic case.

It maybe polarity conscious on the coil connections.

This is a example diagram:

 

[Evans Electric]

I presume the relay has a 24v coil. There should be a connection diagram on the relay, the coil will be obvious, marked across two of the pins, often each side of the keyway, the other pins two sets of three , each set is a changeover contact 1 common to NC or NO (Normally Closed or Normally Open) .

Don't switch the neutral , put 230v feed across common and NO.

Another way could be this . I have just fitted some Eterna NM Emgy fitts , they have a link in them , remove link makes fitting NM , leave link in makes fitting Maintained, remove link and wire switch across it alows you to turn lamp on when required,

Deke

 

[russ9898]

Thanks for the replies everyone.

The camera battery is a little flat at the minute so will put it on charge and post some pics in a couple of hours.

Appreciate the idea of the switched maintained fittings although it wont be acceptable in this case as the client has specified they want the nightlight system to be automated as there isn't always a manager on site. The building is more sheltered accommodation than a care home. Its a funny setup but its a council building and im sure we all know councils can be very stipulative in what they want and overly health and safety concious...although they still dont keep their asbestos report on site even after i was last in the building i found an absolute bollock load of AIB headbang

 

[russ9898]

Pics as promised. If anyone is able to shed a little light on the situation for me. It would be much appreciated.

Thanks,

Russ

 

[oldtimespark]

The relay is polarity conscious Terminal 2 is the positive (+24v), Terminal 7 negative (0v).

Contact set 1:

• Terminal 1: Common Connection
  
• Terminal 3: Normally Open Connection
  
• Terminal 4: Normally Closed Connection
  

Contact set 2:

• Terminal 8: Common Connection
  
• Terminal 6: Normally Open Connection
  
• Terminal 5: Normally Closed Connection
  

To find out the positive rail use a digital volt meter, when connected correctly the meter should read postive voltage as long as the red and black leads are inserted in the correct meter terminals.

Precuations should be taken when live testing.

 

[Lurch]

pin 2 - 24V +ve

pin 7 - 24V -ve

pin 1 - 230V supply

pin 3 - 230V feed to lights

Wire it as above and the supply 24V to the relay and the lights will come on.

 

[russ9898]

Thanks very much for the replies guys. Your help really is appreciated. Now ive been told the connections i can look at it all becomes clear. Hopefully ill get more work involving relays and contactors over the coming years so i can become more confident with them. Not something i did a great deal of during my apprenticeship.

Thanks again

Russ

 

[Evans Electric]

Thanks for the replies everyone.The camera battery is a little flat at the minute so will put it on charge and post some pics in a couple of hours.

Appreciate the idea of the switched maintained fittings although it wont be acceptable in this case as the client has specified they want the nightlight system to be automated as there isn't always a manager on site. The building is more sheltered accommodation than a care home. Its a funny setup but its a council building and im sure we all know councils can be very stipulative in what they want and overly health and safety concious...although they still dont keep their asbestos report on site even after i was last in the building i found an absolute bollock load of AIB headbang

I don't think you can say ballcocks on here !! More importantly , avoid that asbestos !!1

Deke

 

[Lurch]

Novel approach to swear word filtering strikes again.

 

[russ9898]

Little update guys, did the first relay today with 3 lights supplied from it and it worked a treat. Thanks for all your help. Now ive had a little guidance on the wiring of a relay im finding it much easier to understand them.

Roll on tommorow when i wire the remaining 2. Must not forget to label the relay enclosure with warnings of both 230v ac/24v dc either.