To my knowledge, there are 3 methods of splitting the line conductor in each lighting circuit:
Joint box below floor, or above ceiling
Three terminal ceiling rose/batten lampholder
Joint in switch box (neutral)
I am wondering which method is most commonly used in new houses.
I have been in this house for nearly forty years and after upgrading the central heating from warm air to combi-boiler, the Scottish Gas Company's installers connected three smoke detectors to an octopus joint box.
After several years the downstairs lighting occasionally fails. After a time these lights begin to work again.
Being a retired spark, I checked all connections in the CU and they were all secure.
Not knowing where the octopus joint box for the entire four apartment house was located I lifted the fitted carpet upstairs landing and found it.
The line connection had approximately six conductors below a brass plate, but the added line conductor had caused the plate to ride on the additional conductor which was at an angle across the other six. Since the brass connection plate (about one inch long and secured at its centre by a single 2BA or 4mm brass screw had failed to put equal pressure on all conductors, time had caused it to develop an intermittent o/c of the line conductor feeding all downstairs lighting.
Summing up don't you think ALL future new builds should not use the octopus joint box system especially where it is sited below wooden floors with no removable hatch left for access nor even an indication of the position of same.
Joint box below floor, or above ceiling
Three terminal ceiling rose/batten lampholder
Joint in switch box (neutral)
I am wondering which method is most commonly used in new houses.
I have been in this house for nearly forty years and after upgrading the central heating from warm air to combi-boiler, the Scottish Gas Company's installers connected three smoke detectors to an octopus joint box.
After several years the downstairs lighting occasionally fails. After a time these lights begin to work again.
Being a retired spark, I checked all connections in the CU and they were all secure.
Not knowing where the octopus joint box for the entire four apartment house was located I lifted the fitted carpet upstairs landing and found it.
The line connection had approximately six conductors below a brass plate, but the added line conductor had caused the plate to ride on the additional conductor which was at an angle across the other six. Since the brass connection plate (about one inch long and secured at its centre by a single 2BA or 4mm brass screw had failed to put equal pressure on all conductors, time had caused it to develop an intermittent o/c of the line conductor feeding all downstairs lighting.
Summing up don't you think ALL future new builds should not use the octopus joint box system especially where it is sited below wooden floors with no removable hatch left for access nor even an indication of the position of same.
