This is 24V and need to cable up between closer and switched supply.

I have checked the supply does go off with a fire alarm!

What cable should I use? I'd rather use something other than mains cable
to differentiate between mains and ELV.

On Sat, 14 May 2016 22:21:19 +0100, Fredxxx wrote:

This is 24V and need to cable up between closer and switched supply.

I have checked the supply does go off with a fire alarm!

What cable should I use? I'd rather use something other than mains cable
to differentiate between mains and ELV.

I used telephone cable. I ran six pairs from the wiring centre to the
front door, and just used one of those.

The current draw isn't great (on mine, anyway) and the duty cycle is low.



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On 15/05/2016 00:04, Bob Eager wrote:
On Sat, 14 May 2016 22:21:19 +0100, Fredxxx wrote:

This is 24V and need to cable up between closer and switched supply.

I have checked the supply does go off with a fire alarm!

What cable should I use? I'd rather use something other than mains cable
to differentiate between mains and ELV.

I used telephone cable. I ran six pairs from the wiring centre to the
front door, and just used one of those.

The current draw isn't great (on mine, anyway) and the duty cycle is low.

Many thanks for the idea.

Its only a short distance. I would have preferred to have exported an
earth as well, given the cases are metal, and the transformer of unknown
origin.

I was looking for shielded cable or screened twisted pair, then it
dawned on me I can make one conductor earth as well as 0V return!

What current does the solenoid use though?
Brian

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"Fredxxx" wrote in message
...
This is 24V and need to cable up between closer and switched supply.

I have checked the supply does go off with a fire alarm!

What cable should I use? I'd rather use something other than mains cable
to differentiate between mains and ELV.

On Sunday, 15 May 2016 01:06:28 UTC+1, Fredxxx wrote:
Its only a short distance. I would have preferred to have exported an
earth as well, given the cases are metal, and the transformer of unknown
origin.
I was looking for shielded cable or screened twisted pair, then it
dawned on me I can make one conductor earth as well as 0V return!

Fire alarm cables are usually red, I don't know if the door closer wiring has to be too, but I don't think it would do any harm.

https://www.tlc-direct.co.uk/Products/NB1slash2R.html

Screened, available in 2+E and 4+E. Sold per metre.

Owain

On 14 May 2016 23:04:09 GMT, Bob Eager wrote:


I used telephone cable. I ran six pairs from the wiring centre to the
front door, and just used one of those.

The current draw isn't great (on mine, anyway) and the duty cycle is low.

I think he is referring to an electromagnetic door holder rather than
a catch so the duty cycle is more or less 100%. The power consumption
is still low though - typically only 1 or 2 Watts so almost any cable
would be suitable.

On 15/05/2016 09:11, Brian Gaff wrote:
What current does the solenoid use though?
Brian

That's a good question. I could measure the resistance of one.

I assume it can only take a couple of watts.

On 15/05/2016 11:14, Peter Parry wrote:
On 14 May 2016 23:04:09 GMT, Bob Eager wrote:


I used telephone cable. I ran six pairs from the wiring centre to the
front door, and just used one of those.

The current draw isn't great (on mine, anyway) and the duty cycle is low.

I think he is referring to an electromagnetic door holder rather than
a catch so the duty cycle is more or less 100%. The power consumption
is still low though - typically only 1 or 2 Watts so almost any cable
would be suitable.

Yes, it will be permanently on, even when the door is closed, and only
off where there's a fire alarm.

Either way we are talking sub-Amp.

On 15/05/2016 10:30, wrote:
On Sunday, 15 May 2016 01:06:28 UTC+1, Fredxxx wrote:
Its only a short distance. I would have preferred to have exported an
earth as well, given the cases are metal, and the transformer of unknown
origin.
I was looking for shielded cable or screened twisted pair, then it
dawned on me I can make one conductor earth as well as 0V return!

Fire alarm cables are usually red, I don't know if the door closer wiring has to be too, but I don't think it would do any harm.

https://www.tlc-direct.co.uk/Products/NB1slash2R.html

Screened, available in 2+E and 4+E. Sold per metre.

Given the solenoid is fail safe, and power disconnected on alarm, I
don't feel the need to use fire resistance cable. However it would be
smart to make it easily distinguishable from other cabling.

On Sun, 15 May 2016 11:44:56 +0100, Fredxxx wrote:

On 15/05/2016 09:11, Brian Gaff wrote:
What current does the solenoid use though?
Brian

That's a good question. I could measure the resistance of one.

I assume it can only take a couple of watts.

FWIW, a while back I helped my BIL (a builder) release and re-connect
the cabling to a door entry system from a wall he was removing for a
company. The 'fail - safe' door bolt along with the alarm keypad were
run (some distance) to the reception though a multi core cable, the
conductors not much bigger in wire gauge than Cat5 / telephone.

YMMV etc. ;-)

Cheers, T i m

On Sun, 15 May 2016 09:11:50 +0100, "Brian Gaff"
wrote:

What current does the solenoid use though?

24V at 1 to 2W so 40 to 80mA.

Peter Parry wrote in
:

On Sun, 15 May 2016 09:11:50 +0100, "Brian Gaff"
wrote:

What current does the solenoid use though?

24V at 1 to 2W so 40 to 80mA.



Intrigued - how come so little?

On 15/05/2016 19:09, DerbyBorn wrote:
Peter Parry wrote in
:

On Sun, 15 May 2016 09:11:50 +0100, "Brian Gaff"
wrote:

What current does the solenoid use though?

24V at 1 to 2W so 40 to 80mA.



Intrigued - how come so little?

Guess lots of turns!

A solenoid is not like a transformer, where I is purely limited by the
solenoid coil resistance.

On Sunday, 15 May 2016 19:09:56 UTC+1, DerbyBorn wrote:
Intrigued - how come so little?

The solenoid doesn't hold the door open directly - it just holds a latch inside the closer which stops the closer operating.

The solenoids which attach to the wall and are no part of the door closer mechanism probably use more.

Owain

On Sun, 15 May 2016 13:42:47 -0700 (PDT),
wrote:

On Sunday, 15 May 2016 19:09:56 UTC+1, DerbyBorn wrote:
Intrigued - how come so little?

The solenoid doesn't hold the door open directly - it just holds a latch inside the closer which stops the closer operating.

The solenoids which attach to the wall and are no part of the door closer mechanism probably use more.

The figures given were for a solenoid attached to the wall.

On 15/05/2016 21:42, wrote:
On Sunday, 15 May 2016 19:09:56 UTC+1, DerbyBorn wrote:
Intrigued - how come so little?

The solenoid doesn't hold the door open directly - it just holds a
latch inside the closer which stops the closer operating.

The solenoids which attach to the wall and are no part of the door
closer mechanism probably use more.

This is a solenoid on a wall, separate to the closer.

Fredxxx wrote

This is 24V and need to cable up between closer and switched supply.

I have checked the supply does go off with a fire alarm!

What cable should I use?

Whatever will handle the current without dropping too much voltage.

I'd normally use what we call Figure 8, because it is
readily available and has plenty of copper so that
it wont drop too much voltage at any current that
is likely in that situation and quite cheap because
its sold in very high volume.

http://static.rapidonline.com/catalo...17214P01WL.jpg

I'd rather use something other than mains cable
to differentiate between mains and ELV.

Makes more sense to use a different color.