Videx door entry system...voltage drop on 0.5mm²

[The Ghost]

So I have used CW1308 0.5mm² over a 25m. run (2 twisted pairs for 3+1 system). The bottom line is the door release (mag lock) does not work. Call and speech works on the handset so at least the person can be called and pick up the hand set and converse. I am 99% certain the wiring is correct and have the videx wiring diagrams which all look correct to their schemata. I am thinking there is ohms or vd problem so not enough voltage gets to release, so ok I use another twisted pair and double up. Anyone got info on vd and or ohms per m. on CW1308?

 

[westward10]

93ohm/km. The 0.50 is actually the conductor diameter and not the csa it is actually about 0.20mm2.

 

[buzzlightyear]

http://www.fortknoxsecurity.co.uk/files/Videx CABLE SIZE GUIDE1_2.pdf

 

[mhar]

You will likely have a 12v source near the lock, use your twisted pair to operate a relay

 

[ipf]

A while ago we used to do loads of Videx door entry systems. Wired the 12v mag locks in bell wire and the rest in twisted pairs. I'd say volt drop's your problem. Things may have changed, though.

 

[The Ghost]

@p1nkpanth3r you gonna enlighten me as to why it is dumb? Do you know something that may help?

 

[westward10]

One of the ghost dumb posters Vorts the fella has posted once since Feb 2016.

 

[Leesparkykent]

Is the videx PSU 12V ac and the Maglock 12V dc?

 

[DPG]

You could prove the volt drop theory by measuring the voltage at the remote end and comparing it to the supply end. Obviously while the lock is taking current.

 

[Deleted member 26818]

If there are unused cores, add them to those powering the mag lock.

 

[The Ghost]

Is the videx

Yep 12v d.c.

unused cores

Yes that would be the logical thing to do, sadly being a pikey I just got two twisted pairs for a 3+1 system, so either a relay or another cable to pull in then double up. So wish I had got the four pair now.

 

[Deleted member 26818]

When I worked for a company installing door access controls, we used 8 sometimes 12 core alarm cable.
Sometimes we’d use 4 cores for pos and another 4 for neg.