What is a "consumer unit", Rob?
OK, I'm not Rob, but I use the term...
It;s what's commonly called a fusebox (or breaker box). The incoming
mains cable to a house (or simuilar) in the UK goes throguh a sealed
electriciy company fuse, then the watthour meterand then to the 'comsumer
unit;' which the first part owned by the consumer. It consists of a
double-pole main switch and various protectvie devicees (fuses, circuit
breakers, RCDs [1]) wiich then feed the various power circuits and
lighting cirucits of the house.
[1] Residual Current Device. I am not sure if that trem crosses the Pond,
it's a device that detects an imbalance of current in the live and
neutral wires, indicating a leak to earth somewhere, agd turns off the
supply if that imbalance is greater than a certain (small, perahps 30mA)
value.
-tony