All MCCB's in MEM's Memshield 2 range or Bill's Talisman Plus range are branded as such. Even though Eaton bought out Delta in 2003 they maintained the old branding until they came out with the latest range, Memshield 3. Even though they are using the Memshield brand all breakers are now marked as Eaton. Still Confused? Square D was bought out by Schneider in 1991 and although they changed the appearance of the circuit breakers the later versions will still fit the older boards.

Qwikline – This is the most common Square D breaker and the part numbers will always start QO. Available in types 2,3 & 4 with M6 or M9 breaking capacities for early BS3871 breakers or types B,C & D with 6kA or 10kA breaking capacities. These styles have the push-fit electrical connection and push-fit mechanical connection. These are available in single, double and triple pole. Memshield 2 – These are also a commercial breaker and come in types B,C & D. These also will fit into all Memera 2000 range boards.Memera 2000AD – These have a narrow terminal and only fit boards specifically marked Memera 2000AD. They won't fit in older boards. Confused? Well it gets worse because by the time that Delta/Eaton decided that they needed to manufacturer some of the older products to keep the peace with customers the British Standard BS3871 had changed. Previously all MCB's had been marked with a ‘Type' (either 1,2,3 or 4) but BS3871 had changed so that Type 1 MCB's were no longer used and Types 2,3 & 4 were now Types B,C & D. So now you have a range of circuit breakers that are either branded MEM,Delta,Bill or Eaton. They may me marked either Type 2,3,4 or Type B,C,D. Some have a printed wrap around label and some have silk screen printing direct on the MCB. Fortunately the situation with Bill and MEM MCCB's is not as confusing. Firstly MCCB's are made to a different standard to MCB's, BS60947-2. Whilst that standard has been updated to allow for new technologies it still remains as the current British Standard.

So question one does it pass when tested with a RCD tester? If so what makes you think it is faulty? I am sure the one in my old house was tripping due to surges when a neighbour was welding. Two identical RCD's would hold for 18 months without a problem, then trip for seeming no reason for couple of weeks, then again two years no tripping. After 1994 the British Standard of BS60898 came into effect and the range was changed to Types B, C & D and now included double pole mcb's as well. RCBO's were now being widely used and theses were available in Types B & C although it's rare to see Type B in use as most installations were commercial.

Miniature Circuit Breakers (MCBs)                                                                                     

However, just to add a little confusion, some MCB's were discontinued whilst under the MEM brand but due to complaints from customers, specifiers and electrical wholesalers the company had to start manufacturing again. Some of these products are branded Delta and from 2003 some of these products are branded Eaton when they company was bought out yet again. Otherwise, I'm not quibbling the need for proper spur to garage, which will separate off two freezers from kitchen, but how do you people feel about this diagnosis? My own insulation tests with mega meter to each unplugged appliance have found no resistance issues, which given he found no wiring issues, leaves no obvious cause except as he thinks maybe too much total freezer earth leakage. Intermittent faults like tripping can send you mad as we all know, is this a good course of action?