I always wondered what the little holes are for!

[PJElectricalSW]

Found this on my travels today visiting my favourite customers. I hadn't noticed this previously and I can only assume this is the result of a recent 'solar PV service' the customer had last month.

My customer asked for my opinion as she had also not noticed the wire previously, the words 'I dunno, but summat smells fishy' were in my head and on the tip of my tongue but the what came out was "F*ck, that looks ropey as!".

I assume this isn't standard practice to wedge a wire in with a fancy twist to get the 3 phase solar PV to trip. Should the correct item should be a 3 Phase 16A MCB rather than 3 tied together?

 

[Strima]

Cheaper than a bar link.

 

[Toneyz]

Is that a 3 phase MCB or 3x S.P.MCB's?

 

[Phil Thompson]

3x single pole mcbs with a bit of wire ran between the lockout holes as a makeshift conversion to TP

 

[Toneyz]

3x single pole mcbs with a bit of wire ran between the lockout holes as a makeshift conversion to TP

Just was comparing it with the S.P. ones in the D.B. but I suppose they are an older version.

 

[Phil Thompson]

Just was comparing it with the S.P. ones in the D.B. but I suppose they are an older version.

They’re RCBO’s by looks of them.

 

[Deleted account]

Never seen that before. Is it allowed? Does the design of mcb's allow this?

 

[professional]

Linking three devices in such a way is not acceptable as they form an untested assembly.

How would the installer certify compliance? - but then again, PV installers often feel that BS7671 is not applicable to them, a bit like plumbers.

 

[richy3333]

They’re not RCBO’s and it’s just a poor hack to avoid, for whatever reason in using the correct parts?

 

[Deleted account]

They’re not RCBO’s

They look like RCBOs to me. I can see the test button.

 

[Silly Sausage]

They look like RCBOs to me. I can see the test button.

I'd go and get your eyes tested then!
Technical Properties NCN116A - https://www.hager.co.uk/product-catalogue/energy-distribution/protection-devices/mcbs/1-4-pole-mcbs-10ka-type-b-c-d-nbn-ncn-ndn/ncn116a/92304.htm

 

[Toneyz]

They look like RCBOs to me. I can see the test button.

Regarding the other protective devices yes your right they are RCBO's didn't look correctly but I thought that the newest devices had a larger toggle switch like the linked ones.

 

[Deleted account]

I'd go and get your eyes tested then!
Technical Properties NCN116A - https://www.hager.co.uk/product-catalogue/energy-distribution/protection-devices/mcbs/1-4-pole-mcbs-10ka-type-b-c-d-nbn-ncn-ndn/ncn116a/92304.htm

Your link takes me straight to mcb's.
But they are definately RCBO,s next to the 3 phase thing/ 3 mcb's

 

[richy3333]

Your link takes me straight to mcb's.
But they are definately RCBO,s next to the 3 phase thing/ 3 mcb's

Nice attempt to dodge the bullet of being wrong! Why point out what the other PDs are when the op is referring to the MCBs? I’m very confused

 

[ChrisElectrical88]

Haha i have done this before when caught out mis ordering breakers On a out of hours dist board change in a factory. I did of course return as soon as i could with the correct MCB.

 

[Phil Thompson]

The discussion on mcb and rcbos is about what’s beside the 3x SPMCB’s linked together as to why they both look different.

From this quoted posted.

Just was comparing it with the S.P. ones in the D.B. but I suppose they are an older version.

And I said I think they’re rcbos.

 

[PJElectricalSW]

Thanks for replies chaps.

If you hadn't of guessed already, I know naff all about PV. Could anyone explain what this workaround is trying to achieve?

What would happen if the link isn't in and a single phase drops off? Would the invertor be damaged or just a lack of balanced power back to the grid/less generated power being fed back/less income?

 

[Toneyz]

I stand corrected they are RCBO's next to the 3 x S.P. MCB's and the RCBO toggle is smaller than the MCBs hope that clarifies that. The 3 x MCB's have a makeshift link that has not been type tested to operate in simulation.

 

[Deleted account]

Nice attempt to dodge the bullet of being wrong! Why point out what the other PDs are when the op is referring to the MCBs? I’m very confused

Not dodging anything, as you say your a little confused.
Anthony brag was compairing them with the other single pole devices in post 5.
But Phil Thompson correctly pointed out they where RCBO,s in post 6. I agreed with Phil Thompson.

 

[Deleted account]

Ok sorry guys. Especially rich 333. I'm being a bit pedantic with tongue in cheek.
I knew fine well what everyone was refering to, but I couldnt resist confusing matters.

 

[Phil Thompson]

So you’re really Pedantic Pete lmao

 

[Marvo]

If you link single pole MCB's across the toggles like this the spring inside one of the MCB's isn't strong enough to trip all three so it just leaves 2 of the phases connected if there's a tripping fault on one phase.

Replace it with a T/P MCB.

 

[Phillip]

Come on guys and girls, that's a big no no mod. Expected one MCB trip to switch all three is asking a bit much. What if one trys to trip, and the other two mcb's says no your not. I think you can see what could happen next. The big and only answer to thist is get this/who firm to court.

 

[DPG]

Come on guys and girls, that's a big no no mod. Expected one MCB trip to switch all three is asking a bit much. What if one trys to trip, and the other two mcb's says no your not. I think you can see what could happen next. The big and only answer to thist is get this/who firm to court.

I think we already agree on that one.

 

[*-jester-*]

Some 1 pole MCBs can be linked together, I've seen it in control circuits on multi-phase or multiple supplies (essential & non-essential etc) ...but it is achieved using a linking mechanism that connects adjacent MCBs through a removable cover on the side of the MCB.
HOWEVER these link kits usually include a link bar.

So I agree with the consensus that a piece of copper wire used as a link bar is definitely dodgy.

 

[chrisdungan]

Really!!
which ever way you spin this it has a bad feel to it.
Whats the rest of the PV instal like?
DC string or microinverters??
I'd want to cast a very critical eye over the whole PV system.
If it's a DC string system just remember it will be generating high voltage DC not a huge current but if a fault develops in the DC side it can have very nasty consequences

 

[PJElectricalSW]

Thanks for the comments, I don't think the install is particularly good to be honest.

I do not know any details of the installation company and whether the main electrical contractor also installed the PV or not but there are a lot of other very curious installation 'quirks' that I do not think are correct.

The more I look the worse it gets, I have just been fire fighting at the moment doing the critical work. I shall be back in the new year to carry out a full report and tidy the DB. Who knows what lurks inside there but I know rats would be right at home in there!

edit: I guess it would be the last one to touch the board would be in court defending himself (me) and the PV guy should be sweating!

 

[Jymbob]

Hm. Given the feed in tariff is about to vanish I wouldn't be surprised if a lot of questionable companies are throwing out as many installs as they can to clear stock and get their cheques from the government before they quietly dissolve the company and swan off to pastures new!