Contact Joint Problem

[Shawl01]

Other than a junction box can anyone tell me how I can join a potted cable from a new contact to an existing alarm cable?

Background.

I am a recently accredited engineer but find myself with a little challenge of a problem. I have an existing 25mm door contact that has failed in a metal door frame. The existing contact is a CQR FC507 flush mount which is no longer made. This contact just had two terminals on the back the the cable used to go into. As I said the door frame is metal and it is impossible to now run a new cable into the frame as it does not come apart at all. The existing cable cannot be used as a drawer wire as it has been sealed in the fabric of the building.

I cannot fit a replacement 20mm contact as the fixing screws end up over the 25mm hole no matter which way I try. all the replacement contacts I have found in 25mm G2 or above all have a potted cable. The space inside the door frame is very limited and I cannot fit a junction box inside and hence my question.

The customer also does not want surface contacts as this is a school and fears that the kids will break them off.

I want to do this the right way as the system is on police response and unlike my predecessors I do not believe wrapping PVC tape around the tamper switch to be an acceptable solution.

Many thanks in advance for any advice.

Luke.

[datadiffusion]

Something like this with a thin plate and a large flange....?

 

http://www.securitywarehouse.co.uk/catalog/index.php?main_page=product_info&products_id=3322

 

And, welcome to TSI!

[arfur mo]

A piccy woukd soeak a thousand words.

as for surface contact's, roller shutter types are very robust, best secured with blind security bolts, is needed knurl up the threads so can't easily be unscrewed, but if needed can always drilled out later.

[Shawl01]

Hi datadiffusion, thanks for the link, sadly it's a grade 1 contact and I need at least grade 2

 

Hi arfur mo, not sure how this would work, as a roller shutter contact needs two meeting horizontal surfaces, but I have a metal door which sits in a metal door frame so my horizontal surfaces dot have the space for a roller shutter contact.  What am i missing?

 

Thanks for the suggestions though.

Luke

[Alarm Protection]

It's a flush mount Arf!

[Ronnie]

hollow section frames?

[Shawl01]

Hi Super Member +, sadly not!  The frame is not accessible at all from the visible sides at all.  I think the cables must have gone in as the frame went into the wall.

 

Where the existing hole has been drilled, it is clear that the frame has solid cross section in it and lost of sharp metal and no space for a junction box but hopefully enough space to tuck a bit of excess wire.

 

Luke

[Ronnie]

Hi Super Member +, sadly not!  The frame is not accessible at all from the visible sides at all.  I think the cables must have gone in as the frame went into the wall.

 

Where the existing hole has been drilled, it is clear that the frame has solid cross section in it and lost of sharp metal and no space for a junction box but hopefully enough space to tuck a bit of excess wire.

 

Luke

 

solder and heat shrink then

[datadiffusion]

I think the issue is its a 25mm hole and not fillable.

 

This no good riveted or into tapped holes in the metal? 

 

http://www.securitywarehouse.co.uk/catalog/index.php?main_page=product_info&products_id=3322

[Shawl01]

RFS, is soldering allowed then? (Officially)

 

Datadiffusion, I'm not following you.  The link is for a 25mm FC509 which is perfect except it's a grade 1 contact and grade 1 is not allowed on police response?  Am I understanding that right or am i missing something?

 

Thanks

Luke