buried alarm cable near mains

[squowse]

hi. what's the best (and cheapest) way to run an alarm cable to my shed?

also i was intending sharing a trench between mains, telephone and alarm cable but have found out that this is not good because of induction.

would using a shielded alarm cable, or using an interference suppressor (i read of a small capacitor 12V to ground suggested) help? and/or how far away do i need to go from the mains?

also am i likely to have problems with normal alarm cable degrading in the ground??

 

[RF Lighting]

what's the best (and cheapest)

Well which do you want?

You can't have both.

The best will work and last for ages.

The cheapest won't.

 

[squowse]

what's the best (and cheapest)

Well which do you want?

You can't have both.

The best will work and last for ages.

The cheapest won't.

erm... the best then ??

but i don't particularly want to put it in a steel pipe on it's own in a separate trench, if there's a simpler and cheaper way of doing it that will also work. that's what i was getting at, sorry if it was confusing.

 

[breezer]

dig a trench and put in a pvc conduit just for the alarm, then put in a screened cable.

But i Have to ask, why?

If some one does try and break in your shed, what will happen? the HOUSE alarm will go off, any nice neigbours will think its the house being done, not the shed.

I suggest you have a separate alarm for the shed

 

[squowse]

if my alarm went off my neighbours would look out the back first, which is where the shed is, in full view of their back windows and mine. hopefully the alarm would scare off the burglars as soon as it went off?
i am concerned that a separate alarm in the shed would be too vulnerable to attack - ie destroy the bell box when the alarm goes off.

so are you saying i should dig a separate trench for the alarm cable ? how far away do you think?

 

[plugwash]

also i was intending sharing a trench between mains, telephone and alarm cable but have found out that this is not good because of induction.

Assuming you are digging the trench with a conventional garden spade and not some special narrow tool I would suggest using the same trech but running down opposite sides of it. SWA for the mains, and some reasonablly big tube or duct (maybe PVC waste pipe would work) for the telephone/data/alarm stuff.

 

[breezer]

if my alarm went off my neighbours would look out the back first, which is where the shed is,

how do you know human nature says they may wonder whats that noise, oh its an alarm, lets look out side and see who's, where do you suppose the first place will be?, i doubt it will be the back (unless the noise is coming from the back)

 

[squowse]

ok i don't seem to be getting any answer to my original question, just a lot of pedantry.

[EDIT] - sorry plugwash i didn't notice your useful advice when i wrote this. [EDIT]

i know my neighbours, and i know what they do when my alarm goes off. on our houses break ins have always occurred at the back as there is a long wall onto a school with poor security at night. please try not to get upset if it you would do something different.

 

[Spark123]

The mains cable when burried underground should be armoured hence the armouring should create a screen so the issues with running the two together are reduced.
I'm thinking that even though the alarm cable only carries 12v as it is going underground it should also be armoured, similar to the underground phone cables but I am not an alarm engineer!
As another option, can you get wireless transponders for the alarm sensor and scupper having the alarm cable underground alltogether?

 

[squowse]

yes i was wondering if a wireless kit could be obtained to use wireless sensors on a wired alarm. but obviously dearer than dropping a cable in a trench if that will work. if armoured cable has a screening effect that will help. also i will use screened alarm cable. my only issue is the separation. i don't like digging! i suppose the alarm cable could be shallower as it's not affected by regs. the whole trench will be overlain by paving slabs (ie a path) so i know where it is and no prospect of digging through it.

 

[Spark123]

I am not sure that a screened alarm cable is suitable for burial in the ground. I know when they bury phone cables they use armoured ones. What do the alarm engineers do?

 

[breezer]

I am not sure that a screened alarm cable is suitable for burial in the ground.

i was not intending the screened cable to buried directly, but to go in a conduit

squowse, you would pay more IF you can find "bolt on" radio kit that a screened cable would cost

 

[squowse]

ok. is the conduit intended to be watertight?

 

[breezer]

ok. is the conduit intended to be watertight?

only in the middle (since either end will be in doors or inshed)

 

[Spark123]

Does the conduit need to be metallic to provide mech protection in the ground?