There’s debate about exposed basic insulation in meter cupboards being satisfactory or not? Industry guidance (WRAG) say it’s satisfactory if the door’s in good shape, what’s people views on this ?
There’s debate about exposed basic insulation in meter cupboards being satisfactory or not? Industry guidance (WRAG) say it’s satisfactory if the door’s in good shape, what’s people views on this ?
It seems absurd to me to have exposed basic insulation where it's fully expected that unskilled unsupervised people will, and indeed by design, should, have access (since they're expected to able to read the meter). In this case the triangular key does nothing to restrict access, since everyone in the household will have access to it. Unlike say sockets or switches that could be opened by a common or garden screwdriver, there isn't even the common sense restriction that it's something not normally to be opened by the unwary.
It's like saying bare conductors are satisfactory in an office, or broom cupboard, if the door needs a key to open it.
Yet by the wording of the regs, both would seem to comply. It's a strange world.
- Andy.
Broadgage and Andy sum it up.
"Key or tool" - the fact that they are readily available hardly meets the intention that access should be restricted to more than ordinary persons.
I am tired, so I am not going to plough through the Big Brown Book, but C3 for me. Poor workmanship!!!
It's like saying bare conductors are satisfactory in an office, or broom cupboard, if the door needs a key to open it.
How so? the conductors are not "bare" in this case.
However, just to be 100 % clear, bare conductors in enclosures of equipment to designated standards, for example, are acceptable ... provided the enclosure provides an appropriate IP rating, and the conductors are appropriately separated, it could well even be sufficient for double or reinforced insulation !
"Key or tool" - the fact that they are readily available hardly meets the intention that access should be restricted to more than ordinary persons.
That's interesting. Where does BS 7671 say that only skilled persons (electrically) or instructed persons (electrically) should have the keys or tools giving access to enclosures?
The concept of "access by key or tool" is a long-standing one in electrical safety standards.
(Although, does this mean it's time for a change?)
That's interesting. Where does BS 7671 say that only skilled persons (electrically) or instructed persons (electrically) should have the keys or tools giving access to enclosures?
A key (or tool) implies that access should be restricted to a particular person or class of persons. If not ordinary/skilled or instructed, is the distinction between adults and children?
Perhaps the idea of having a key to the meter box, as opposed to a simple knob, is nothing to do with safety, but to deter theft?
Those ghastly white boxes are relatively new. The meter used to be indoors, which presented a problem if the premises were unoccupied when the meter-reader called, so putting them in a box with a key (albeit a simple one) on the front wall made sense. If that was the purpose of meter boxes, they are now obsolete, so please may we get rid of them?
A key (or tool) implies that access should be restricted to a particular person or class of persons. If not ordinary/skilled or instructed, is the distinction between adults and children?
BS 7671 doesn't say that ... it just implies "make it harder" ... there are also requirements to provide warnings.
At the end of the day, most people (skilled, instructed, or otherwise) have access to tools that can open up their domestic appliances ... is that a problem?
On the other hand "key or tool" goes back to the time when we had open switchboards in industrial sites ... controlled access as you say ... but it's hardly an "open switchboard".
Conversely, my home has access only by a key ... can I post a warning notice and wire the whole installation indoors with singles with no containment ?
Hmmm ... "double standards" ??
If anyone has suggestions as to how to "square the circle" as it were, I'm sure the industry would be grateful, but I don't think there's an easy answer.
It's like saying bare conductors are satisfactory in an office, or broom cupboard, if the door needs a key to open it.
I completely agree. If we find single insulated cables in a cupboard we can't just lock the door and put a label on the door. It's bonkers. Do the job properly and not cut corners.
Gary
Conversely, my home has access only by a key ... can I post a warning notice and wire the whole installation indoors with singles with no containment ?
You can wire it with bare conductors on dainty porcelain insulators, if you wish. You would be safe, but I doubt that Donoghue v Stevenson would let you get away with it should anybody else be injured.
Back to the OP: does any significant risk arise from short lengths of exposed inner insulation?
Conversely, my home has access only by a key ... can I post a warning notice and wire the whole installation indoors with singles with no containment ?
You can wire it with bare conductors on dainty porcelain insulators, if you wish. You would be safe, but I doubt that Donoghue v Stevenson would let you get away with it should anybody else be injured.
Back to the OP: does any significant risk arise from short lengths of exposed inner insulation?
Back to the OP: does any significant risk arise from short lengths of exposed inner insulation?
In a meter cabinet where the conductor insulation is not generally exposed to UV, the only issues we might have are the result of mechanical damage, or the possible external influences of flora & fauna (although the latter could apply if the sheath were present).
In my example of "whole house" or, more widely, in general, conductor insulation might not be protected against UV, but a sheath might.
So, in the general case, yes potentially a problem ... in the case of a meter cabinet, probably not (most of the time) if the door is intact and usually left closed.
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