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Advice Please - Mains cartridge fused Isolator switch or MCB and isolator Switch.
Former Community Member
I manage a residential mobile home park with homes that individually have mains supply TT coming to a meter box recessed into a breeze block shed. The tails then come from the meter into the shed and into an old style bakelite rewireable 40a fused isolator switch. There is then an outgoing 10mm SWA cable running from the isolator switch underground from the shed to the home and then into the consumer unit for the home (total run approx. 8 to 10 metres). Having had an EICR for one of the homes I have been adviced that these isolator switches will need to be replaced as the swa cable is not properly terminated (it is not glanded in to the isolator switch and the wire stranded sheathing is twisted together and connected to the earth block.) My question is can this isolator switch be replaced with an 18th edition 3 way metal enclosure with double pole isolator switch and 40a mcb or should it be replaced with a 60a (or 40a) cartridge fused double poled mains isolator switch. Additionally would it a be a good idea to put a 60a RCD into the shed and either use a five way enclosure (in place of 3 way enclosure) or a 2 way enclosure fed from the cartridge isolator switch. All the homes have a standard consumer unit containing either a 60a or 80a RCD and 3 to 5 suitable MCB's (32a, 16a, 6a).
It is difficult/impossible to fit an SWA gland to those old switchfuses, so I am not surprised at the way this has been done. Purists may say this is a bit scruffy but provided the armour is correctly terminated to Earth and the sheath continues into the Switchfuse it is not a codable item. In fact, this is the way in which most incoming "modern" split concentric cables are terminated into the distributors fuse. If the switchfuses are in good condition no action is required. Should you wish to replace the switchfuses, any kind is acceptable, a metal enclosure is not mandated as this part of the installation is not domestic. I suggest a cartridge type fuse rather than an MCB, it will cause you less problems with faults inside the home..
As you will see elsewhere, I am collecting EICRs with incorrect coding and I would like a copy of yours, particularly if the coding is C1 or C2, and a photograph of the inside of a switchfuse if you feel you could provide it. If an estimate for the change is also provided I would like that too if possible. davezawadi (at) yahoo.co.uk.
It is difficult/impossible to fit an SWA gland to those old switchfuses, so I am not surprised at the way this has been done. Purists may say this is a bit scruffy but provided the armour is correctly terminated to Earth and the sheath continues into the Switchfuse it is not a codable item. In fact, this is the way in which most incoming "modern" split concentric cables are terminated into the distributors fuse. If the switchfuses are in good condition no action is required. Should you wish to replace the switchfuses, any kind is acceptable, a metal enclosure is not mandated as this part of the installation is not domestic. I suggest a cartridge type fuse rather than an MCB, it will cause you less problems with faults inside the home..
As you will see elsewhere, I am collecting EICRs with incorrect coding and I would like a copy of yours, particularly if the coding is C1 or C2, and a photograph of the inside of a switchfuse if you feel you could provide it. If an estimate for the change is also provided I would like that too if possible. davezawadi (at) yahoo.co.uk.
