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

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.

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

Edited August 4, 200817 yr by steveo44

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

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.

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

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

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

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?

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.