Testing some flats in a retirement home, every mains unit has a doorbell transformer module in it, the 12 volt cable is obviously inside the mains unit. Its just unsheathed bell wire and the installers have made no attempt to separate it from the 240 stuff. I was going to give it a code C2 but the owners are going to flip when they find out every flat needs work. Is there any way anyone would consider giving this a C3 code and leave it as it is. I know I'm only there to do a report but they will think I'm trying to buy work if I condemn it as it seems a trivial problem to most.
Has it ever complied to an edition of the regs? If not, it's not a C3! Oversleeving the bell wire with some flexible tube or sleeve is all that would be required.
I thought C3 meant it does not comply with current regs but is not dangerous. Good idea to sleeve it but all the cables come from behind the plasterboard and into the rear of the CU. I suspect the bell wire is just bunched in with these. Even if it is sleeved though it could potentially come loose out of the transformer and touch the bottom of an MCB its next to, bad design all round really, I would like to see it outside the mains unit.
It is more often used for something that complied at the time of design/construction, but doesn't comply now, because of a change in the Regulations.
Ask yourself this, Peter. Do you honestly feel that in a million years this would realistically present any problem whatsoever. If you code that you are mad.
I think it will be absolutely fine, indeed I have done something similar in my house regarding a 12 volt relay and some outside lights, however I have to put my name to something and say it complies when it doesn't. I haven't been asked to pass or fail the installation, its just a form that lists the condition of it. In the unlikely event that something did go wrong then I don't think I would get any favours of the victim if it did. There are various other little things wrong as well like single conductors not doubled over in MCB or neutral terminals but I don't see this as a danger even if it did go wrong so may let them slide.
There are various other little things wrong as well like single conductors not doubled over in MCB ----------------- You're not seriously suggesting that should be coded are you Peter! And where does it say conductors not doubled over in mcb's is wrong? (admittedly a good idea in most cases though)
Guessing your new to this game PP? I wouldn't even waste either the ink on the hand from or the wear an tear on my tablet in coding that mate, honest.
What I would do is disconnect the bell wire from the transformer (both + and -) and then crock onto earth (maybe met near) and crock the bell wire - if it measured an appreciable induced voltage then I would start asking questions tbqh.. Questions like 1 - Do I give it a code 1? 2 - See if I could find the geezer/s who did the job and ask - scuse guv are you aware of the ''segregation of circuits'' regs?
Guessing your new to this game PP? I wouldn't even waste either the ink on the hand from or the wear an tear on my tablet in coding that mate, honest. _______________________________ Not new to the game but I don't do PIRs day in day out. If it doesn't comply to the regs then it need coding, surely. If it was just wrapped round the mains cables outside the CU then it would not bother me, just like all the other small things I found. This building is only 5 years old, it should be done to a lot better standard than it is.
Voltage Band I is defined as levels of voltage which are too low to provide serious electric shocks; effectively this limits the band to extra-low voltage (ELV), including telecommunications, signalling, bell, control and alarm circuits. Voltage Band II covers all voltages used in electrical installations not included in Band I. This means that all 230/400 V (240/415 V) supplies are included in Band II. As expected, BS 7671 prohibits Band I and Band II cables sharing the same cable enclosure or multicore cable unless: every cable is insulated for the highest voltage present, or each conductor in a multicore cable is insulated for the highest voltage present, unless conductors of the two bands are separated by an earthed metal screen, or they are installed in separate compartments of a trunking or ducting system, or they are installed on a tray with a partition providing separation, or a separate conduit or ducting system is provided for each band. I don't know what bell wire insulation is rated at - myself light 2 core oval would be a better bet in these type of installations - unless there is a stranded bell wire with a heavier insulation produced - then this would be ok I suppose, but you might just as well use two core light oval.
There are several defined parts to this. Wiring system, circuit, voltage, voltage Band I, voltage Band II. Looking at the definition of wiring system a consumer unit is classed as a wiring system. An assembly made up of cable or busbars and parts which secure and, if necessary, enclose the cable or busbars. Circuit is an assembly of electrical equipment supplied from the same origin and protected against overcurrent by the same protective device(s). In a.c. extra low voltage is not exceeding 50V. Low voltage is >50V but not exceeding 1000V. ELV will normally fall within voltage Band I, and LV in voltage Band II. 528.1 deals with Proximity to electrical services. Having carefully considered all the requirements I agree with you that mounting a 12V transformer on the DIN rail with bell wire output is non-compliant with reg 528.1 unless one of the measures listed (i) to (vi) are adopted. If you must code it I think C3 is adequate. . Definitely not a C2.
Thanks sinewave, I see you haven't changed, so whats wrong with being thourough? Some of the terminations in this place are terrible, like the 3 phase boards in the communal areas, they are MEM Eaton boards with those awful RCBO clip on module things, the live turret is about 6 inches deep and half the time the installer has missed clamping one of the two browns. I've rectified all these though as I had to disconnect anyway to test. The main bonding under every sink is bad too, no lug and not even doubled over round the screw, just under one side of the clamp, half are loose. Every back box is half a mile in the wall with long screws, does nothing for the fire rating. Someone has converted a room upstairs into a staff kitchen and run half a dozen sockets spurred off a ring on the floor below. All the heavy stuff like the section boards and SWA look good though, the firm has obviously had their experienced electricians doing the distribution stuff and then got the lackeys in to final fix.
I am sure one of the test rigs in college was wired up in this way and most of us said it was sloppy and pretty sure we were told it would be a 2 if it were being inspected.
Sloppy wiring can be commented on, but you can't just go coding things YOU don't like. No lugs on the bonding? Not worth a breath. Nothing wrong with this at all. Loose ones, sure. Doubling over conductors? If the termination is sound, there is nothing wrong. Most people don't double over in MCB terminals, just terminals where screws bite down. Eaton boards are high quality - Good kit has been fitted. Shame people can't terminate the RCBO's correctly. If the back boxes are in rendered walls, no problem, although not great. If in stud walls, extension colours should be fitted to keep the fire rating. With the bell wire, you could try to confirm the voltage rating, but would need the brand. Most, I believe, it rated to only 100v. You need to be careful coding things with a C2 - This causes an "unsatisfactory" outcome. I'm not saying don't code it. A C3 is generally used for things that complied once, but no longer do, but I guess a C3 would be your best option here, if you really want to code it. Remember, you can just comment and not code. The Amtech software gives you this option.
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