Went to install a Elucian consumer unit today - Not happy with the SPD Config - Page 1
Forum section: electronics / general

author: TheBay
author_rank: Unknown
timestamp: August 04, 2025, 06:27:39 pm
content: Bit of a rant here, but thought I would share.So I decided to try an Elucian board as I need to use 1P+N RCBO's and Hager don't do any single module B Curve RCBO's with a switched neutral.It was a tossup between this Elucian and the new Fusebox F3 range, but this was slightly smaller and I thought may be ever so slightly better quality than Fusebox.However one thing I noticed today when I unboxed it was how they have configured the SPD, they are now using a single module SPD (Looks to be the same SPD as BG and Contactum) that has the N/L on the top and the PE on the bottom. The problem with this is as they don't use an MCB for the SPD the cables coming out of the SPD go directly in to the main live bus bar. So both terminals on the main switch are shared, I'm not so bothered about the neutral side as that can just be moved to the neutral bus bar, but it really does bother me that the small live cable for the SPD is in the same terminal as the live bus bar for a number of reasons.Firstly the cable is quite small and has a small surface area, so when situated in the cage terminal on the main switch the cage doesn't have much purchase to push against the bus bar. Also this cable isn't ferruled at all, it has just been shaped and dipped in to a solder pot. Soldered stranded cables in any type of terminal, cage or not are just not a good idea imho. I do wonder about this working loose over time.It also got me thinking, it's bad enough trying to get a bus bar in devices when a board is on a wall making sure the cage on each device is the right side of the bus bar, then to have a cable going in to the main switch as well is a further pain. Now I know that I need that cable underneath the bus bar so the whole surface area of the bus bar is against the fixed part of the main switch terminal and not against the cage.It also crossed my mind about someone installing these and not thinking or not realising how the terminals are actually connected up internally in a device like a main switch and they put the cable on top of the bus bar by accident or not knowing which side they should put it. The whole load on the bus bar would end up passing through the end of this cable which is a small surface area as the bus bar itself won't be in full contact of it's whole surface area. Not only that, if the cable is above the bus bar then the bus bar will be a few mm out in height with all the other neighbouring devices a well.Anyway I'm a bit puzzled to why they are using this terminal configuration on the SPD as every other manufacturer that does not use an MCB with the SPD has the live terminal on the bottom of the SPD so it can go directly on the bus bar and not have this unnecessary issue and one that has the potential to be quite dangerous. Also it begs the question, is this SPD even designed to work without an MCB, does it have an internal fuse or some form of OCP as it is the older design with terminals on the top to wire directly to a MCB, it seems silly if they have gone to the effort of re-designing this and not put the live on the bottom like every other manufacturer so it can go directly on the bus bar.Personally I don't know if I want to fit it if that's how these are and may go change it for a Fusebox F3 or something else from the wholesaler.

author: AVGresponding
author_rank: Super Contributor
timestamp: August 05, 2025, 05:18:06 am
content: That isugly.ime and imo it's not a good idea to mix cable sizes in a single termination; it invariably results in the larger being over-tightened while the smaller is under-tight.

author: Monkeh
author_rank: Super Contributor
timestamp: August 05, 2025, 05:32:24 am
content: Quote from: TheBay on August 04, 2025, 06:27:39 pmThey all have an internal thermal fuse as it's not possible for a decoupled device to effectively protect them. An MCB is a waste of time - nothing an SPD does will ever trip a B32 as usually fitted, or even a B6.

author: TheBay
author_rank: Unknown
timestamp: August 05, 2025, 12:02:28 pm
content: Quote from: Monkeh on August 05, 2025, 05:32:24 amAt least there is some potential protection for any SPD devices that use a flying live lead, on this device if that 6mm2 lead was to chafe or get caught against the chassis there is absolutely no protection at all other than the DNO Fuse.I've taken some measurements today.The surface area of the tinned wire is 3.9mm x 1mm which is much smaller than the bus bar comb, not only that as mentioned it is just tinned. This is all that is keeping the bus bar in contact with the main terminal of the main switch/isolator.

author: themadhippy
author_rank: Super Contributor
timestamp: August 05, 2025, 12:15:21 pm
content: Quotebrilliant,give it some time and it'll need tightening up again,cut the bugger off and put a male spade crimp on it

author: TheBay
author_rank: Unknown
timestamp: August 05, 2025, 12:21:01 pm
content: Quote from: themadhippy on August 05, 2025, 12:15:21 pmWhat worries me is there are probably 100's if not 1000's of these out there by now and this could be a serious fire risk.Hager used to use a flying lead like this on their SPD's but they use a fork terminal which went in the upper terminals on the isolator leaving the lower cage terminals free for just the bus bar.

author: Monkeh
author_rank: Super Contributor
timestamp: August 05, 2025, 04:22:33 pm
content: Quote from: TheBay on August 05, 2025, 12:02:28 pmTrue, but also an extraordinarily unlikely failure mode in practice. An argument for a nice formed bar rather than a lead, though.SPDs really should just go on the bus bar like anything else. And using proper double bus bars is long overdue at this point.

author: TheBay
author_rank: Unknown
timestamp: August 05, 2025, 05:07:31 pm
content: Quote from: Monkeh on August 05, 2025, 04:22:33 pmIt's quite a soft silicone and only seems to be a single layer of insulation, it could easily get nicked by accident when someone is installing or working on the board. Tails have to have multiple layers of insulation and most new boards have clamps now.If this wire got damaged it would be the same as the tails getting damaged, except this is only 6mm2 and imho I wouldn't like to bet on that blowing the DNO fuse.

author: themadhippy
author_rank: Super Contributor
timestamp: August 05, 2025, 05:45:53 pm
content: Quoteput em in an enclosure and you can use single insulated,same with the clamps no need if you use a stuffing gland

author: TheBay
author_rank: Unknown
timestamp: August 05, 2025, 06:08:45 pm
content: Quote from: themadhippy on August 05, 2025, 05:45:53 pmThat's interesting actually as that might answer something I've been pondering.I have 10mm SWA that will feed this CU, instead of going directly in to the CU I have gone in to a large Wiska box, this is more for isolation as I can isolate the DNO PE on the SWA armour as it's a non-conductive box. From the Wiska box to the the CU will be singles, now as it is SWA and it is in an enclosure does that mean cables with single layers of insulation can be used instead of double insulated tails? The SWA has a MCB and TD RCD before it.

author: Monkeh
author_rank: Super Contributor
timestamp: August 05, 2025, 06:21:52 pm
content: You only need double insulated cabling where it's exposed - inside an enclosure is not exposed. You can just pull the cores all the way through the box into the CU as long as it's got a coupler between or is butted up tight.

author: TheBay
author_rank: Unknown
timestamp: August 05, 2025, 06:58:45 pm
content: Quote from: Monkeh on August 05, 2025, 06:21:52 pmIt's a bit different with a TT system though if there is no TD RCD before the CU as it's a class 1 enclosure.I just had a quick read of the regs and I wondered if the fly lead on that SPD wouldn't comply in a TT installation."Regulation 531.3.5.3.2.201 requires that, where Class I enclosures are used (that is, earthed metalwork) on TT systems with RCD protection on outgoing circuits, all live conductors on the supply side of the RCD – that is, the internal cable links – must have double or reinforced insulation."Although it is on the output side of the main switch, that would be the supply side to any RCD's or RCBO's.

author: Ranayna
author_rank: Super Contributor
timestamp: August 06, 2025, 08:30:08 am
content: Quote from: TheBay on August 05, 2025, 12:02:28 pmI'm not an eletrician, let alone know much about UK wiring except what i saw in JW's Youtube Videos.But is that really allowed? I thought ferrules or crimped connectors were mandatory in electrical installations when stranded wire is terminated.

author: Whales
author_rank: Super Contributor
timestamp: August 06, 2025, 08:52:16 am
content: Quote from: Ranayna on August 06, 2025, 08:30:08 amI am also under the impression that putting solder into screw-compression style fittings is verboten.The screw-compression cages are made of a (plated) copper alloy. The wire is made of copper. A bootlace ferrule is made of a (plated) copper alloy. These things all have similar thermal expansion coefficients (EDIT:approx 17e-6/degreeK)Solder does not. It's approx 24e-6/degreeK for leaded and 22e-6/degreeK for pure tin. It will expand & shrink more than the copper screw compression cage.I am lead to believe this mismatch will cause it to deform & loosen or creep out over repeated thermal cycles?

author: TheBay
author_rank: Unknown
timestamp: August 06, 2025, 09:46:54 am
content: Quote from: Whales on August 06, 2025, 08:52:16 amAbsolutely my thoughts and it will be Pb Free RoHS solder which has it's own inherent problems.I've contacted the manufacturer today and sent off an email to them, hopefully they will look in to this as it is easily resolved with a slightly different design of SPD.I will keep this thread updated.

author: Whales
author_rank: Super Contributor
timestamp: August 06, 2025, 09:59:27 am
content: Quote from: TheBay on August 06, 2025, 09:46:54 amIf you mention that then they'll misinterpret it as a suggested solution"He mentioned how to fix it, and also leaded solder" "Oh we need to use leaded solder to fix it? OK"On a more serious note: could they have used an alloy that's matched to copper's coefficient of thermal expansion? Do such alloys exist that look like silvery coloured shiny solder? I doubt it, but for all I know it's a common thing for exactly this problem across an entire industry.

author: Whales
author_rank: Super Contributor
timestamp: August 06, 2025, 10:05:05 am
content: Huh. Is this actually solder?Look at the bottom where the copper is stranded. I can't see any infiltration of solder between the strands, it's a night and day transition between silver and copper. I would expectsomesolder to wick down into there.Could it instead be a thick ferrule crimp that has been mega bashed into shape? Do you have the sample still lying around? A cross section would be interesting regardless of what it is, even a rough one made with sidecutters.

author: TheBay
author_rank: Unknown
timestamp: August 06, 2025, 10:06:07 am
content: Quote from: Whales on August 06, 2025, 09:59:27 amHah, that's a good pointThe OEM that manufactures their SPD's already do one with the Live terminal on the bottom so it would just sit directly on the live DIN Rail, I told them this would actually save them money as they would no longer need to supply a live fly lead. I thought money saving and penny pinching would appeal to them more than anything else.

author: TheBay
author_rank: Unknown
timestamp: August 06, 2025, 10:08:01 am
content: Quote from: Whales on August 06, 2025, 10:05:05 amIt's definitely not a ferrule, and its very soft metal.Even if it was terminated correctly, the surface area is too small to push against the bus bar comb which is 4x the size.

author: Monkeh
author_rank: Super Contributor
timestamp: August 06, 2025, 11:43:02 am
content: Quote from: Ranayna on August 06, 2025, 08:30:08 amThey're not. However, good workmanship and suitable materials are.

author: Gyro
author_rank: Super Contributor
timestamp: August 06, 2025, 12:39:39 pm
content: @TheBay: Zooming up the 3rd image in your OP, The SPD markings don't show the 'T2' in a square box or a fuse rating indication (normally 100A gG) to indicate that it is a Type 2 SPD - check Toolstation / Screwfix for Axiom, BG, Wylex, Crabtree,etc SPD product images for Type 2 markings. The Type 2 ones have the Line connection on the bottom for direct connection to the busbar (I think you mentioned that the OEM makes one of these too).If it isn't a Type 2 then I think it does need an MCB for safety, or at least to meet regs. If they haven't included one (and there are no other markings on the non visible sides of the SPD) then I think Elucian are on very dodgy ground here.EDIT: I don't know if any of these other products would fit (exact height of the busbar clamp is obviously critical), and you also have the issue of non manufacturer approved device.

author: TheBay
author_rank: Unknown
timestamp: August 06, 2025, 12:54:47 pm
content: Quote from: Gyro on August 06, 2025, 12:39:39 pmYes you do raise a valid point there and I did wonder if it wasn't compliant as all the SPD devices I have seen that do not require an MCB have "100A gG" written on them with a fuse symbol and this doesn't.However it does indicate it is a type 2 as it has T2 in a square box, this isn't that clear on the pictures I've uploaded.The previous generation of these SPD's were also T2 but were always provided with an MCB.I've attached a picture of the BG Version which has the fuse symbol and "100A gG", this is the version that does not require an MCB and has the live terminal on the bottom. The previous BG version does not state this and although T2 was always fitted with an MCB - I've attached a picture of this version too.

author: Gyro
author_rank: Super Contributor
timestamp: August 06, 2025, 01:08:32 pm
content: Hah, it's difficult to see in the image, but it almost looks as if they've stamped on the T2 by hand, it looks slightly twisted and not aligned with anything. It definitely counts as small-print anyway!It's hard to know on the MCB, as Monkeh says, it probably doesn't do anything in practice (other than adding inductance). When SPDs first came out, they didn't fit MCBs, then they started appearing in CUs and manufacturer instruction, only to disappear again with T2s. The regs have that useful catch-all of 'though shalt follow the manufacturer's instructions'. If Elucian have stamped a little T2 on it then maybe that covers it, but how do you know the installation is compliant if they don't specify a maximum upstream fuse [Edit: / protection device] rating?Puzzled.

author: TheBay
author_rank: Unknown
timestamp: August 06, 2025, 01:15:07 pm
content: Quote from: Gyro on August 06, 2025, 01:08:32 pmI really don't think this is compliant as it should have 100A gG with a fuse symbol and it does not have that. I have just informed the manufacturer about this too.

author: Monkeh
author_rank: Super Contributor
timestamp: August 06, 2025, 05:16:17 pm
content: Type 2 has nothing to do with needing an MCB or not - it's about the type of surge they're designed to handle. These will pretty much always have been Type 2 devices, as Type 3 is inadequate at such a low impedance position and Type 1 is intended to handle direct lightning strikes, which is not generally a concern in most smaller installations.Marking a suggested protective device does not appear to be a requirement of IEC 61643-11 - but if one is required it must be indicated somewhere (not necessarily on the front). I don't have a current copy of IEC 61643-11, though.

author: TheBay
author_rank: Unknown
timestamp: August 06, 2025, 05:26:19 pm
content: Quote from: Monkeh on August 06, 2025, 05:16:17 pmIt doesn't seem to be on there anywhere, I know on the Wylex SPD's it's indicated on the side of the cartridge.

author: TheBay
author_rank: Unknown
timestamp: August 07, 2025, 09:38:17 pm
content: Just a quick update.The manufacturer is involved now and it is all being investigated by various teams. I have been sent an initial official response to the matter and I have replied with some further findings.