Do I need a type A RCD for a new boiler mains supply?

Boilers do not require 30mA RCD protection. However, likely as not the circuit used to supply the spur to the boiler will to have it. Don't be concerned about type A versus type AC RCDs. The main reason they were developed is to enable them to operate if the coil gets saturated with DC leakage current. This is a problem for EV chargers, for example, and lighting circuits with large numbers of LEDs. Boilers do not leak DC current! So ignore the British Gas persons comments. They hear about a new device and make assumptions. Its typical of the misadvice they often give. They should stick to gas and not get involved with the electric side.

It is always interesting to hear the opinions of gas fitters(sorry engineers) on what is and is not a compliant electrical installation. The design of electrical installations takes account of different types of RCDs and their correct use. When selecting the correct RCD for a specific installation the designer should take in to account the nature of the equipment that may be supplied. At the time your installation was designed type AC RCDs were deemed adequate. The electrician was asked to alter the installation and install a FCU for the boiler. Unless your electrician was specifically told the FCU was to supply equipment that required a Type A RCD then the job has been completed to original specification. If the manufacturer of the boiler supplied and fitted by British Gas does specify a Type A RCD then you should have been made aware of this before making alterations to your electrical installation. If you where not told of this requirement then I am not sure how you are liable. Furthermore, they have now fitted a boiler that requires a Type A RCD and you have Type AC protecting your installation they have left your installation in a potentially dangerous state. Let me explain why it is potentially dangerous. The boiler installed may have the protentional to 'blind' your Type AC RCD to other faults. So, it may not operate when it should. The RCD is there to protect you and your family from serious electrical shocks should a fault occur. I would get in touch with British Gas and ask them why they left your property in such a condition.

Assuming that you had a combi boiler recently installed this only require a very little amount of power to "spark" and get the boiler started. Type A RCDs trips from AC currents and DC pulsating currents and are now the new standard but a AC type RCD is perfectly suitable to cover a combi boiler. Hope this helps

If i was replacing a fuseboard, I would install type A Rcbos and a surge protection device to all circuits to fully comply with current regs. The problem is that certain modern appliances such as washing machines with digital inverter drive motor can stop a type AC rcd from operating. The problem with fuseboards is that most customers don't really know what they're paying for and are ending up with cheap bg split load fuseboards with type ac rcds which aren't compliant with current regulations.

From 28th September 2022 he is correct and at the moment we are going through a transition phase so amendment 1 and amendment 2 are compliant. To keep track with changes in technology the wiring regs frequently change; if the boiler manufacturer recommends a type A is fitted then the BG man is correct. The consumer unit fitted with type AC was compliant at the time of fitting and type A's may not have been readily available at that time. Interestingly Germany prohibited the use of Type ACs in the 1980s so the UK is a bit behind. So much for the 17th edition electrical harmonisation with the EU!