surfisup1000:

 

gregmcc:

 

With the common use of microprocessors and micro electronics, the size, price and reliability of RCD's are well affordable.

 

 

They are not 'that' cheap, and a pain in the ***** if poorly installed (why do electricians check their own work!!).   We had regular RCD trips in the house, largely caused by cumulative circuit leaks rather than any specific fault. Had a different but really good electrician install an RCD on every circuit to spread the load better.  I think the switchboard RCD's were around $100 each or so? And 20 or so circuits in the house.  Total cost was around $2500 from memory.  

 

But, safety is important...electricity is just super dangerous. Read some of the plug safety certifications....impressive engineering goes into a simple plug. 

 

That's not really on the electrician - poorly specified, not poorly installed, unless you want to count chasing down all your faulty appliances as part of installation. At least unless HWC/oven were put on RCD when not required to be. And most people don't really want to pay an extra $2k for limited additional security of supply.

Current standards have changed (a while back) to no more than three circuits per RCD (previous was any number, common practice minimum 2 RCDs to limit impact of one fault). This is partly due to total leakage current, but mostly limiting the impact of trips.

RCDs, as noted, are specified to prevent fatal shock. 10mA & medical grade ones are somewhat more sensitive, but they will still allow a notable shock without tripping, and take time to trip. The surprise and pain can still be substantial, and as noted, make you fall off a ladder.

Isolation transformers will continue operating through a fault, though you won't know it. That means you can do slightly dumb stuff like operate moderately faulty/wet gear without being shocked.