Have you been told you need a 17th Edition consumer unit (fuse board) for your house?
17th Edition Consumer Unit – Here we explain what that means and what the options are (4 main ones).
There are at least 4 different types of 17th edition consumer unit that can be used to comply with the current wiring regulations. It isn’t the consumer unit itself that complies with the regulations, it’s the way your electrician groups the circuits inside the unit in order to reduce the likelihood of nuisance earth fault tripping (among other things). Your electrician can utilise any one of the following fuse-boards to comply with the regulations:
1. Dual RCD Consumer Unit– Comprises one isolator and two RCD’s (earth trips) – Your electrician will arrange the circuit breakers between these 3 devices in order to comply with the 17th Edition Wiring Regulations. The whole installation can usually be done with standard MCB’s (Miniature Circuit Breakers) and the additional more expensive RCBO’s (MCB and RCD combined) should not be required.
3. Triple RCD Consumer Unit– Comprises one isolator and three RCD’s – Your electrician will arrange the circuits between these 4 devices in order to comply with the 17th Edition Wiring Regulations. The whole installation can be done with standard MCB’s (Miniature Circuit Breakers) and the additional more expensive RCBO’s (MCB and RCD combined) will not be required. This 17th Edition consumer unit solution is becoming more popular as it gives more flexibility without resorting to RCBO’s.
4. Isolator Only Consumer Unit – Comprises one isolator only – Your electrician will use RCBO’s on nearly all the circuits providing earth fault protection to each individual one ensuring compliance. This is in most cases the best solution for a 17th Edition Consumer Unit as it provides individual localised protection for each individual circuit with the least possibility of nuisance tripping of unaffected circuits. it is usually however the most expensive in terms of parts (not labour).
The bottom line is that the electrician is responsible for using the most appropriate solution to suit your installation, so it’s best to check with them first before making any purchasing decisions.
**PLEASE ALSO SEE – The 2015, ‘Amendment 3’ update to the 17th Edition Wiring Regulations (The above information is still valid, but from Jan 2016 all new domestic consumer units should be non-combustible)**