- Reaction score
- 20
Has any manufacturer come out with a compliant flush mounted CU? The ones I can see have either a plastic back and a metal door or a metal back and a plastic door.
It looks as if compliant CUs will have to have opaque metal doors. In this case I can't see the point of the door being some sort of flap - why can't the door cover the whole CU as you see in distribution boards? The Germans cracked this years ago see e.g. the ABB Striebel&John CUs or the Hager Volta CUs which have plain metal doors which are relatively inconspicuous even if mounted on the wall of a living room. The problem is that these CUs all have plastic backs not metal backs as far as I can see.
But anyway what is the basis that they should be metal? Amendment 3 421.1.201 specifies that CUs shall "comply with BS EN 61439-3 and shall have their enclosure manufactured from non-combustible material". BEAMA has published clarification that this precludes glow-wire rated plastics but what authority do they have? Surely it should be in the amendment if the rule is that specific? The new on-site guide section 2.2.6 repeats the BEAMA clarification but on what basis? Surely the IET-published on-site guide should take its information from its regulations not from some other third-party's opinion, however well-regarded. The glow-wire tests are specifically designed to show that plastics are non-combustible so why do they not comply? IET should provide justification for why only metal CU's qualify for the non-combustible material rule.
It looks as if compliant CUs will have to have opaque metal doors. In this case I can't see the point of the door being some sort of flap - why can't the door cover the whole CU as you see in distribution boards? The Germans cracked this years ago see e.g. the ABB Striebel&John CUs or the Hager Volta CUs which have plain metal doors which are relatively inconspicuous even if mounted on the wall of a living room. The problem is that these CUs all have plastic backs not metal backs as far as I can see.
But anyway what is the basis that they should be metal? Amendment 3 421.1.201 specifies that CUs shall "comply with BS EN 61439-3 and shall have their enclosure manufactured from non-combustible material". BEAMA has published clarification that this precludes glow-wire rated plastics but what authority do they have? Surely it should be in the amendment if the rule is that specific? The new on-site guide section 2.2.6 repeats the BEAMA clarification but on what basis? Surely the IET-published on-site guide should take its information from its regulations not from some other third-party's opinion, however well-regarded. The glow-wire tests are specifically designed to show that plastics are non-combustible so why do they not comply? IET should provide justification for why only metal CU's qualify for the non-combustible material rule.
