Type C or B rcbo? & Results on a CU change certificate

[Gavin John Hyde]

Been to quote for a job this morning, The house has 2 CU's one is eco7 for 5 storage heaters, the other was upgraded in 2009 and all wylex rcbo's. Meter tails, bonding all up to scratch, the DNO upgraded the cutout to PME in 2009 with the previous work.
The owner is going to have the heaters replaced with more modern efficient ones and do away with the eco7 to have single tariff, The ec07 is old wylex rewireables and wants it updated.
So I intend to replace the plastic main Cu with a larger metal one, incorporating all circuits into this, utilising existing main switch and rcbos where possible, i then only need 5 rcbo's for the heater radials. and a larger CU shell. Not sure on what rating rcbo's yet as I need to know what heaters are fitted.
However, what i noticed made for interesting reading, he pulled out the old paperwork for the Cu change in 2009 and the invoice/paperwork from dno for the PME.
The person who did the work previously replaced the CU, installed type C rcbo's, changed tails, bonding etc but failed to record or bother doing any r1, rn, r2 or R1+R2/R2 tests! the certificate has blank spaces! makes me doubt its worth..
Thoughts on the existing type C rcbo's.. my normal approach would be for type B's. I did some tests this morning and the Zs, Ze and IR appear okay. I didn't test all the circuits as i will be going in once the heaters are fitted by the German outfit end of June. All circuits are quite short and testing showed good Zs results and within allowed for type C. A type B would give higher allowed Zs so not sure why he didn't fit them in 2009??
end to end on rings is okay, slight variance between line and neutral, likely a loose connection..
Question is to what extent am i responsible for previous circuits if im not changing the rcbos, merely putting them in a new enclosure, im fully respsonsible for the new ones i add and circuits I connect up.
Thoughts and ideas?

 

[Pete999]

Would imagine, if you are putting a larger VU in, then an EIC will be required, hence you will be responsible for ensuring ALL the circuits comply with BS 7671

 

[Andy78]

Would imagine, if you are putting a larger VU in, then an EIC will be required, hence you will be responsible for ensuring ALL the circuits comply with BS 7672

BS 7672:1993 - Specification for compression, stiffness and labelling of anti-embolism hosiery - https://shop.bsigroup.com/ProductDetail/?pid=000000000000311221

 

[Gavin John Hyde]

I dont think the last guy took responsibility mind... left half the certificate of results blank!

 

[Andy78]

Yes you should test and issue a cert for all connected circuits, whether or not you re-use the RCBOs.
No idea why continuity results were not recorded, or why the last three circuits are listed as 5 second disconnection time. Maybe worth a thorough test before doing the work.

 

[Pete999]

BS 7672:1993 - Specification for compression, stiffness and labelling of anti-embolism hosiery - https://shop.bsigroup.com/ProductDetail/?pid=000000000000311221

Sorry Andy got sausage fingers again, close though, I'm sure you know what I meant, going to the shed now, to beat my fingers with a hammer, see if that helps, lol

 

[Andy78]

Sorry Andy got sausage fingers again

Just tickled me with it being compression socks. Thought you might have been doing research for your work with old folks.

 

[Gavin John Hyde]

I will be doing some proper testing before the actual CU replacement.. I will have to visit to check the new heaters rating, cables etc... and to liaise for DNO to pull the fuse so I can fit an isolator thats hes requested aswell.

 

[Ian1981]

If the test cert is from 2009 then why are they 5 second disconnection times stated for water heater circuit and lights?

 

[ipf]

At a guess, it could be that when the original CU was replaced, the client didn't want to pay for a full test and inspection resulting in the installer doing global IR test, including Zs results whilst testing RCDs, making sure no serious problems existed.
There is no need for a full T+E if changing a CU, remember.

 

[suffolkspark]

have you told him there's no such thing as more energy efficient electric heaters

 

[Gavin John Hyde]

Hes got some German outfit installing these ceramic heaters with some sort of coil inside, supposedly used less energy for a higher performance and output... sounds a bit like perpetual motion if you ask me!

 

[suffolkspark]

I know the ones you mean, they are okay, and look ok, but... it will no doubt cost him more than economy 7 did.

 

[PEG]

My guess would be that his supplier has prompted the alterations,as most likely dropping the option of dual metering.

The storage heating can be economical,but ONLY if the insulation/air movement work is done first and completely.

You can jam any German coil you want,in a bog standard semi,and you will most likely just end up with more digits on the bill

 

[The Ghost]

to beat my fingers with a hammer

Is that the fingers on both hands? Just a bit worried you may be stuck with the second hand/fingers beating.

 

[westward10]

My thoughts on the Type C, none. You say you are not sure why he did not fit Type Bs due to the higher max Zs. Fitting Type B will not change the nature of the installed circuit and the Cs fitted are fine. I nearly always fit them on lighting circuits.

 

[Wilko]

My thoughts on the Type C ... I nearly always fit them on lighting circuits.

Interesting - after being called back to Mrs Muggins " 'cause lectrics off " caused by a dying lamp, this may help (?).

 

[Ian1981]

We all know they type C devices are for higher than wanted inrush currents so if they are necessary then use them if not then I personally don’t see the point and might as well stick to B type they require less fault current for them to operate.

 

[buzzlightyear]

and to liaise for DNO to pull the fuse so I can fit an isolator thats hes requested aswell.

could you not get the tooth fairy's to pull the fuse why they are pulling kids bad teeth out or do you call them in to put a isolator in.

 

[Gavin John Hyde]

could you not get the tooth fairy's to pull the fuse why they are pulling kids bad teeth out or do you call them in to put a isolator in.

Owner insisted on getting dno to pull the fuse...hes done his research.... he had them upgrade cutout to pme in 09.
Also the cutout is in a low awkward spot where youd be on knees to pull it when you are my height!!! Its in an adjoining cupboard... figure they can pull it if hes paying. He also has a smart meter.. last time the fairies visited a smart meter home the meter made a right noise... beep and high pitched noises
They quoted him nearly 200 quid to fit a dp isolator! So instead they are pulling fuse and ill fit it for him as part of the wider job. It makes my life easier too.