"Having bought a number of these, I can empathise with the previous reviewer’s comments.
Neutral: • These are “non-latching” which means if you get a power cut, they will switch themselves off and stay switched off. They will not come back on when the power is restored and you will need to physically push the re-set button before they will work again. I would recommend a latching RCD for any unattended appliances that need continuous power. E.g. The chest-freezer in the garage • The Masterplug latching type is no longer available but there are other makes around. (Note: Newlec & JCB are from the Masterplug stable) • The size and shape of a RCD means that you need to ensure there is adequate space around the socket
Negative: • Masterplug regularly change the design with the best version some 3 modifications ago • There is no longer a lifetime guarantee on the product which probably speaks volumes about the manufacturer’s quality problems • To remove the terminal cover you need a carpenter’s Pozidrive PZ1 screwdriver as the sleeving on an electrician’s screwdriver is usually enough to stop you accessing the screws (trust me on this) and a Philips PH1 screwdriver won’t work either • The casing is not especially robust and liable to break when dropped • As soon as unpacked, check for trip mechanism faults by plugging it in unfitted and press the test and reset buttons. This is the most common problem - one can get a tad apoplectic when, once fitted, they show up as faulty • Whilst most of them are OK, the inconsistent quality means I don’t have a great deal of faith in the product but luckily, have the where-with-all to PAT test and check the trip-speed at the time of every fitting
Positive: • They are comparatively inexpensive but becoming less so • If they work on day one, they usually work well and will generally stay working. I haven’t found many that fail in service • They are reasonably fast, tripping at around 14 m/sec on a 20 metre lead. Most other makes I’ve tested are slower and at 230 volts, the difference between 14 and 40 m/sec can be eye-watering"