TNCS systems I've seen before have not had a few strands of the sheath with black insulation, that's what's confusing me. Also, there is usually a PME warning sticker put in place by the DNO but there isn't one in this case?
If I record the worst-case reference method then wouldn't questions be...
I haven't done any testing for a long time so some help with a few questions muchly appreciated please!
Firstly, earthing. The supply cable (from underground) appears to have several strands of the sheathing coated in black insulation and which is used as the neutral with the remaining bare...
The system was TT, but changed to PME during a change of cut-out. I called them in because the cut-out was damaged and I wanted it replaced before I renewed the CU. Never got round to measuring Ra, but will do when I re-connect, although it's probably not so important now with PME connected...
It's running off an MCB in the house. All other circuits in the house are RCBO, so no problem with discrimination.
I s'pose my question is: is there any advantage to having the PME system backed up by the earth rod? (I think so)
And if not, is there a disadvantage to having the two earthing...
Sorry, that boring subject again about which so much has been written. However, I would just like to hear views on the following: 6mm 3 core swa running off 40A MCB from consumer unit in house. Armour and 3rd core connected to PME in house. This feeds an RCBO'd consumer unit in new building in...
Thanks for your comments guys... have now discovered that the electric oven is being replaced for a gas one, so feel a bit better about it now :-) still interested to know where to get hold of a shower interlock should I need one at some point....
Two existing 10kw showers, will pull about 86A if used simultaneously. They haven't had problems in the past, but it's a big house which is being refurbished, including a garage to office conversion which will add extra load. While I'm at it, I wanted to make sure there's no future problems...
About to do a consumer unit change and noticed that the 100a supply is feeding two electric showers. Clients say that the showers are not used simultaneously but may well be in the future. Does anyone know where to buy a 'non priority interlock' so that I can do this job properly and avoid any...
Most u/f elements have a 'lifetime guarantee' now so the manufacturers must be pretty confident of their longevity. I haven't done many but the ones i did almost 10 years ago are still going strong :-)
Still after ideas regarding the access for thermostat cable. I was considering sinking a...
The themostatic probe in the floor needs to be accessable, in case it needs replacing in the future. I don't think it's good practice to plaster it in and tile over it! That's why I'm after new ideas on how people do this...surely not everyone just plasters over the wires?? :confused5:
So, I don't need any special gland to earth the aluminium tube, and I can terminate straight into an MCB in the CU. Niceic guy also said that it doesn't need double pole protection if straight from the CU. For piece of mind I will replace the main switch in the CU with a time delayed RCD.
All I...
This surprises me. I have always assumed that being concealed in a wall, or under a wooden floor, would carry the same degree of risk. I have just confirmed with niceic guy who agrees that it seems a little silly, but you're absolutely right. :)
If I can persuade them not to stuff the floor around the cable with insulation then maybe this will be possible! I've never used this stuff, how is it terminated with regards to the aluminium tape? Surely this has to be earthed in order for it to be suitable for use without the need for RCD...
I have said that the cables will be concealed in the floor, under floorboards...which has the same implications as being concealed in the wall.
Flexishield is great, but only upto 6mm (32 amp) which is not big enough. 40A is required here. :)
No, I haven't considered MICC, but from what I remember the terminations will be quite bulky?
The main issue here is the cable protection and shock protection. If I use swa, then I don't need an RCD at supply end but will need KMF. With this I will also need a box to terminate the swa before it...
I was assuming that all unprotected cables had to be rcd'd now, are you saying that if it's over 32amp it doesn't have to be? Do you think that rather than a KMF and an rcd, a double pole rcbo would suffice? It's a bit tight so need to keep as compact as possible!
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