Hi All,
This is my first post. I have a Home Automation company specialising in high-end residential projects. I've been in the industry for more than 15 years, but it is the first time I've encountered this particular issue. I'm not a qualified electrician, thus the contracted electricians will do the lighting wiring into our DB's that contain our circuit breakers and dimmer/relay modules.
At this particular site we had 10 DBs in various locations, but the main DB and our main lighting DB were in the basement plant room. The wiring was done as follow:
* Council mains into wall box with large main input breaker and 4 copper bars (3 phase and neutral)
* Wall box to about 10 x 3-phase breakers, each supplying the various other DB's throughout the house, but one set of cables go straight from the copper bars onto the breakers at the top of our lighting DB next to this main DB.
* Our breakers in our DB are then linked with a 3-phase bus bar - 12 x 10A breakers
* We have a Earth connection bar at the top of our DB and a Neutral bar at the bottom. Inbetween is our 8 channel dimmer and relay modules.
* The Twin-and-earth cables get split at the top of our DB so the earth gets connected at the top earth connection block, the live gets connected to the dimmer output and the neutral at the bottom connection block
No for the issues...
With so many twin-and-earth cables at the top and people looking for cables and pulling cables, ext. Somehow one of the earth cables snapped and touched the top of the 3-phase bar. This caused all sorts of weird things, but wouldn't it have been saver if we had our own 3-phase input breaker instead of the supply coming straight from the mains box copper bars?
Also, some pumps have now blown at was connected to other DB's, but shouldn't these have been connected to earth leakage?
How can a short between earth and live not trip any breakers? We had to run and switch DB's off.
Thanks for any advice.
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