Difference Between Grade2/grade 3 Door Contacts

[Amps]

Is the only difference that Grade 3 contacts have the resistore all ready fitted ?

[james.wilson]

Nope, resistors are irrelevant for grading.

A grade 3 contact must among other thing either detect the presence of an external magnetic force that could bypass it, or be immune from it.

[Amps]

Thanks redbull. So whats a grade 2 contact? Where can i find what is neede for grade 2/3 systems? everyone i speak to seems to have different ideas

[james.wilson]

very similar to the old BS4737 ones, but with tamper detection using a tamper switch complaint with the std. ie not the 2 metal tabs the old jb's had. They are Grade 1 now

[Amps]

very similar to the old BS4737 ones, but with tamper detection using a tamper switch complaint with the std. ie not the 2 metal tabs the old jb's had. They are Grade 1 now

The grade 3 contacts i have been fitting still have the 2 metal tabs for the tamper! Castle care-tec with resistors pre fitted.

[james.wilson]

they are old Grade 3 ones then, from before the reg change, cqr by any chance?

[Guest anguscanplay]

very similar to the old BS4737 ones, but with tamper detection using a tamper switch complaint with the std. ie not the 2 metal tabs the old jb's had. They are Grade 1 now

but not juntion boxes

[james.wilson]

yep jb's too. Its to do with the enviroment class and that tabs corrode etc

[Guest anguscanplay]

yep jb's too. Its to do with the enviroment class and that tabs corrode etc

section 9 says "....but is optional in grade 1 and grade 2"

though I was thinking about this today - why dont we have to tamper the BT block?

[james.wilson]

But i thought we were discussing G3?

But re tampering of BT joint, where would you stop?

As a tool is required to disconnect the block it isnt tampered, if the line was disconneted at the block, to dp, the pole etc the panel will report a line fault. Same with IP as long as a tool is required then its ok, what you cant do is use a std cat 5 socket and patch lead as no tool is req to disconnect. There is a whole guide on signalling connection location etc coming from the BSIA. Ie no comms in entry routes etc

But again this is all only G3, G2 as a low to medium risk can just be plugged in which is why IMO G2 will over the next few years be accepted less and less.