Earth Bonding Gas & Water Pipes

Or if not looped around the crew, for a bare section to be opened up 3 strands and 4 strands and the screw fitted between?


I don't think so Clive. Reading BS951 (albeit the 1999 copy). 5.2 suggests that the termination shall be capable of being possible to loop in and out.


I've always read this as the conductor under the screw shall be of equal size under both sides of the screw head. Taking an extreme example, 10 mm2 one side and 4 mm2 the other side would grip the 10 mm2 but leave the 4 mm2 loose. Do you agree Clive?


I would consider this to apply also to 4 and 3 strands as you describe.


I would also think that putting the 10 mm2 under one side, ie without looping round the screw to be also a no no.


If I were to find the conductor as you describe with 3 strands one side and 4 strands the other side, I would observe and record that the installer to obtain confirmation from the manufacturer that this method of using his product in this manner is compliant with BS951. Not one installer has forwarded this confirmation so has elected to simply re-terminate by looping round the screw with 7 strands each side. 


Whilst this may appear to some practitioners as harsh, the effort in removing a piece of insulation and forming the conductor into a loop round the screwdriver and then putting the screw through it, might take a few seconds longer than jabbing the screwdriver through the strands to separate into 3 and 4.


Regards


BOD

Or if not looped around the crew, for a bare section to be opened up 3 strands and 4 strands and the screw fitted between?


I don't think so Clive. Reading BS951 (albeit the 1999 copy). 5.2 suggests that the termination shall be capable of being possible to loop in and out.


I've always read this as the conductor under the screw shall be of equal size under both sides of the screw head. Taking an extreme example, 10 mm2 one side and 4 mm2 the other side would grip the 10 mm2 but leave the 4 mm2 loose. Do you agree Clive?


I would consider this to apply also to 4 and 3 strands as you describe.


I would also think that putting the 10 mm2 under one side, ie without looping round the screw to be also a no no.


If I were to find the conductor as you describe with 3 strands one side and 4 strands the other side, I would observe and record that the installer to obtain confirmation from the manufacturer that this method of using his product in this manner is compliant with BS951. Not one installer has forwarded this confirmation so has elected to simply re-terminate by looping round the screw with 7 strands each side. 


Whilst this may appear to some practitioners as harsh, the effort in removing a piece of insulation and forming the conductor into a loop round the screwdriver and then putting the screw through it, might take a few seconds longer than jabbing the screwdriver through the strands to separate into 3 and 4.


Regards


BOD