Obsolete Bill, MEM and Delta Circuit Breakers

mem-eaton-billBill Switchgear was probably one the oldest British electrical brands and was especially known for bigger switching devices like triple pole fuse switches and switch fuses and LV panelboards. The company was aquired by Delta in 1973 who also owned another well known brand, MEM.

Delta decided to keep the brands MEM and Bill separate until 1998 when they finally phased out the Bill brand. What most people don’t realise is that all the products that were manufactured were identical in both brands. Delta manufactured the products and either labelled them MEM or Bill.

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.

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.

Long and short of it is this. All brands, no matter what Type, colour or creed are interchangeable with each other. So if you are stuck for a Bill MCB, then a MEM, Eaton or Delta will still fit. Likewise if you can’t find a particular MEM version then Bill MCB will be a direct replacement.

Moulded Case Circuit Breakers (MCCB’s)

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.

As with MCB’s all MCCB’s were manufactured by Delta and either branded MEM or Bill. They are identical apart from the logo and and a slight difference in the part number. You won’t find any branded Delta, they never used that branding on any moulded case breakers.


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?

If you are still stuck for an obsolete Bill or MEM circuit breaker and this has just confused you even more then please get in touch via our contact page and we will be only too glad to help out.