Ferdinand Posted January 23, 2017 Share Posted January 23, 2017 (edited) On another thread @Steptoe commented on my electrical setup: Quote The Unit is a QFS-RRM24FLEXI 20-way from Control Gear, and seems quite solid. The upgrade was notably good value. http://www.controlgeardirect.co.uk/ A quick note @Ferdinand Those are only Single Pole RCBOs, IMO not really fit for purpose tbh, You can get daisy chain faults as the neutrals don't disconnect. And, totally not permitted on TT systems, only can be used on TN, I'd advise anyone considering using RCBOs to ensure they are DP, I have had a look around and my RCBOs are to BSEN 61009-1, and I think that it is OK if not quite latest best practice. GIven that the setup meets regs circa 2014 I think I am reasonably happy. A few questions if I may: What is a TT system and a TN system? What are the differences and how can I tell which one I have in place? This is my consumer unit. Ferdinand Quote Edited January 23, 2017 by jack "SIngle" --> "Single" in subject :-D Link to comment Share on other sites More sharing options...
Guest Alphonsox Posted January 23, 2017 Share Posted January 23, 2017 I posted this link on another thread which explains the differences according to the IET :- http://electrical.theiet.org/wiring-matters/16/earthing-questions.cfm?type=pdf Link to comment Share on other sites More sharing options...
Ferdinand Posted January 23, 2017 Author Share Posted January 23, 2017 Thanks @Alphonsox Can you point me to something shorter e.g. One page which will help me find out which system I have in place? eg do I look in the meter box and trace it back visually until I find an earthing point? Cheers F Link to comment Share on other sites More sharing options...
Steptoe Posted January 23, 2017 Share Posted January 23, 2017 3 hours ago, Ferdinand said: Thanks @Alphonsox Can you point me to something shorter e.g. One page which will help me find out which system I have in place? eg do I look in the meter box and trace it back visually until I find an earthing point? Cheers F Can you post a picture of your cutout,? ie, the incoming supply fuse and cable. Link to comment Share on other sites More sharing options...
Ferdinand Posted January 23, 2017 Author Share Posted January 23, 2017 39 minutes ago, Steptoe said: Can you post a picture of your cutout,? ie, the incoming supply fuse and cable. Will do later. Link to comment Share on other sites More sharing options...
Ferdinand Posted January 23, 2017 Author Share Posted January 23, 2017 Here we are. It is all in the meter box. Not very good photos, I am afraid. Link to comment Share on other sites More sharing options...
Ferdinand Posted January 23, 2017 Author Share Posted January 23, 2017 To my eye the green label "PME" suggests it is a "TN-C-S (PME)" (from the link) system which - based on the initial comments above - suggests compatibility. Ferdinand Link to comment Share on other sites More sharing options...
SteamyTea Posted January 23, 2017 Share Posted January 23, 2017 Why is it so messy in the DNO boxes. I would have thought by now that they would have come up with a nice neat design that incorporated a DP switch after the fuse and meter. Really is ridiculous that they have not moved on since the 1940's. Link to comment Share on other sites More sharing options...
ProDave Posted January 23, 2017 Share Posted January 23, 2017 10 minutes ago, SteamyTea said: Why is it so messy in the DNO boxes. I would have thought by now that they would have come up with a nice neat design that incorporated a DP switch after the fuse and meter. Really is ridiculous that they have not moved on since the 1940's. They have. SSE almost always install a meter with a built in isolator. Link to comment Share on other sites More sharing options...
Steptoe Posted January 23, 2017 Share Posted January 23, 2017 26 minutes ago, Ferdinand said: To my eye the green label "PME" suggests it is a "TN-C-S (PME)" (from the link) system which - based on the initial comments above - suggests compatibility. Ferdinand 100% correct TN-C-S and a claimed PME system (they aren't always) , but they have to state them as such to comply with ESQCR TBH , most new installs are actually proper PME, well, the new bit anyway. Link to comment Share on other sites More sharing options...
SteamyTea Posted January 23, 2017 Share Posted January 23, 2017 At least that is a start. There are only 6 houses where I am, we have 3 different meters, but only 1 DNO. This is something that the industry sort sort out, not exactly an anticompetitive move. Link to comment Share on other sites More sharing options...
Onoff Posted January 23, 2017 Share Posted January 23, 2017 1 minute ago, Steptoe said: 100% correct TN-C-S and a claimed PME system (they aren't always) , but they have to state them as such to comply with ESQCR TBH , most new installs are actually proper PME, well, the new bit anyway. Look out for poles where the pikeys have hacked off the intermediate earths on rural PME systems as far up as they can reach! Link to comment Share on other sites More sharing options...
Ferdinand Posted January 23, 2017 Author Share Posted January 23, 2017 Cheers all. I shall now sleep soundly. However a power cut killed my microwave this morning so I need a surge protector for the replacement. Link to comment Share on other sites More sharing options...
Onoff Posted January 23, 2017 Share Posted January 23, 2017 (edited) 6 minutes ago, Ferdinand said: Cheers all. I shall now sleep soundly. However a power cut killed my microwave this morning so I need a surge protector for the replacement. Up front domestic SPDs, there's a thought! Bedtime reading: https://www.hager.co.uk/files/download/0/4540_1/0/Surge_Protection_Guide.pdf Edited January 23, 2017 by Onoff Link to comment Share on other sites More sharing options...
Jeremy Harris Posted January 23, 2017 Share Posted January 23, 2017 24 minutes ago, SteamyTea said: Why is it so messy in the DNO boxes. I would have thought by now that they would have come up with a nice neat design that incorporated a DP switch after the fuse and meter. Really is ridiculous that they have not moved on since the 1940's. If you think that wiring is messy, have you ever seen French wiring? A friend owned a big house in the Loire that had originally been the hunting lodge for the nearby château. It needed a lot of doing up, having never been intended for occupation, just day use, and came with a lot of outbuildings, 20 acres of chestnut woodland and half a dozen cottages. He gradually restored the place over about 12 years and converted some of the cottages to holiday lets (I've stayed there many times, and flown around there - he used to runs the flying school at the nearby airfield). What amazed me was seeing French electricians first fix. They chase flexible conduits into the walls, and the concept of a "safe zone" for wiring is completely lost on them. The general rule seemed to be to run the wires by the most direct route, so they would literally run conduits diagonally across walls, with nothing running vertically or horizontally as we would do it. They also seemed to always use single conductor wire for everything, just pulling as many wires through a conduit as needed. TBH, it looked chaotic to me, and I can't imagine what it must be like when you come to do something like hang a picture or fix anything to a wall. It must be essential to ALWAYS use a cable finder, as, judging on what I saw, there could be cables under the plaster absolutely anywhere! Link to comment Share on other sites More sharing options...
SteamyTea Posted January 23, 2017 Share Posted January 23, 2017 (edited) " It looks as if it was put in by an Indian. " Prince Philip Edited January 23, 2017 by SteamyTea Link to comment Share on other sites More sharing options...
PeterW Posted January 23, 2017 Share Posted January 23, 2017 39 minutes ago, SteamyTea said: Why is it so messy in the DNO boxes. I would have thought by now that they would have come up with a nice neat design that incorporated a DP switch after the fuse and meter. Really is ridiculous that they have not moved on since the 1940's. I noticed that new installs by WP have a neatly sloping incomer with the fuse in it that means there is no odd bend in the cable - also means the meter is much less cramped towards the top of the box. We had the supply listed as the final supply point so I've also had to fit the isolator and a Henley in there so it's looking tight but hopefully they will be ok as the whole of the left side of the cabinet is free.... Link to comment Share on other sites More sharing options...
Jeremy Harris Posted January 23, 2017 Share Posted January 23, 2017 10 minutes ago, Onoff said: Up front domestic SPDs, there's a thought! Bedtime reading: https://www.hager.co.uk/files/download/0/4540_1/0/Surge_Protection_Guide.pdf Funny old thing but I've been looking at SPDs recently, as we've had a spate of nasty spikes on the supply, ever since there was a major cable replacement programme a year or so ago, following a lot of damage by high winds bringing some major cables down.. In our case the situation is exacerbated because our supply voltage never drops below 240V, even in winter, and is often right on the 253V limit on a sunny day. It restricts my PV export a fair bit of the time, as the inverter throttles back to maintain no more than 253V. Several of us on the same supply have had stuff fail due to surges (I lost one of my Makita battery chargers a couple of months ago by leaving it on during a storm) and our PV inverter has shut down around three times now, with the diagnostics showing it was due to an over-voltage spike. The problem is that I really need to do some more investigation to find out how big the spikes are, first, to see if it's always lightning (I think it is, as it seems to coincide with stormy weather) or whether it's just over-voltage events (like an inductive load turning off when the local grid is already at peak voltage). Trying to get the DNO to drop a tapping on the sub-station seems to fall on deaf ears, even though a few of us on the same feed can see that the voltage is always at the high end of the allowable tolerance band, of +10%, -6% around 230 VRMS. Link to comment Share on other sites More sharing options...
Steptoe Posted January 23, 2017 Share Posted January 23, 2017 3 minutes ago, PeterW said: I noticed that new installs by WP have a neatly sloping incomer with the fuse in it that means there is no odd bend in the cable - also means the meter is much less cramped towards the top of the box. We had the supply listed as the final supply point so I've also had to fit the isolator and a Henley in there so it's looking tight but hopefully they will be ok as the whole of the left side of the cabinet is free.... As long as its not a DP Henley (proper name ISCO btw) , like that widowmaker @Ferdinand has Link to comment Share on other sites More sharing options...
PeterW Posted January 23, 2017 Share Posted January 23, 2017 2 minutes ago, Steptoe said: As long as its not a DP Henley (proper name ISCO btw) , like that widowmaker @Ferdinand has How do you mean...? Link to comment Share on other sites More sharing options...
Ferdinand Posted January 23, 2017 Author Share Posted January 23, 2017 I'm worried again now. We have a widow in the house already and don't need any more . F Link to comment Share on other sites More sharing options...
Steptoe Posted January 23, 2017 Share Posted January 23, 2017 21 minutes ago, PeterW said: How do you mean...? @Ferdinand has an ISCO with both Line and Neutral cables being connected, These are very prone to cracking inside , then the next time someone knocks it, or tries to remove the cover,,,,,, Prepare to meet your 40 virgins, Link to comment Share on other sites More sharing options...
PeterW Posted January 23, 2017 Share Posted January 23, 2017 Ok so what is the alternative...? Pair of single block Henleys..? Reason I ask is that is what we have fitted in line with 17th Edition so if there is something wrong I'd like to know before the meter is installed and before Amelie the seal fairy has to come and visit.... Link to comment Share on other sites More sharing options...
Ferdinand Posted January 23, 2017 Author Share Posted January 23, 2017 Just now, PeterW said: Amelie the seal fairy has to come and visit.... Onk! Onk! Onk! Onk! Onk! Link to comment Share on other sites More sharing options...
Steptoe Posted January 23, 2017 Share Posted January 23, 2017 DP ISCO are quite permitted in the regs, but I would only ever fit them as a last resort and space really was that tight, they are a smidge smaller than 2xSP blocks, but not by much, Also, SP gives you the option of entering either end , (oh err,), Your isolator switch should be between the block and the meter anyway, so that should provide isolation even when sealed. Link to comment Share on other sites More sharing options...
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