ELECSA Certification Scheme Elecsa Part P Scheme - Testing Queries

[Geoffsd]

make sure the funds have cleared into their account and you'll be fine.

If they haven't you won't need to worry about the questions.

 

[ray-bentos]

Just been to assess the job this evening ahead of tomorrows job, noticed what could be a problem.

The shower is an 9.5KW on 6mm T&E. The cable goes up from the CU to the ceiling clipped direct to wall, perhaps 2m within the void between down & upstairs (so would assume clipped direct in there, no thermal insulation to worry about) upon where it goes up through an airing cupboard (again, clipped direct) to the switch in loft (no insulation covering) and back down again to the shower (as far as I can tell all clipped direct). Its currently on a 32amp MCB but I plan to up this with new CU. If it was an install I had done myself I would have changed for 10mm however after some discussion with my customer (MUM!) upgrading the cable is out of the question (IE: it worked fine before....)

According to OSG 6mm clipped direct is good for 47amp, and as its only a short run (I estimate maximum 12m) volt drop is only 3.2V so well within value. I haven't used a clamp meter to confirm exactly what current is being drawn (my clamp meter is only cheap so not the most accurate) however if we work on worst case scenario (9500/230=41.3) can I use a 45amp MCB, should provide protection against short circuit (bearing in mind 6mm REF method C) within the capabilities of the cable, and note on some sort of design sheet my calculations to show I'm not just trying to wing it?

 

[ray-bentos]

Yeah the funds cleared don't worry!
Its just my first time thats all, probably getting all worried about nothing!
Safe isolation is always number 1, got a lock off kit so all good. I don't have a lockoff tag for my kit though, is that really a requirement for domestic work?
And what about the health & safety policies and risk assessments for a sole trader? Everything seems geared towards employers so not sure if thats required as I don't employ anyone (yet...)

 

[Kate]

Im sole trader and I have to have them. Just find some generic ones from internet and tailor them to u. No sign for lock off should be ok for domestic

 

[ray-bentos]

what you think to the 6mm issue?

 

[GLENNSPARK]

if you mean the main earthing then use the adiabatic to prove its good for time/current...

 

[ray-bentos]

if you mean the main earthing then use the adiabatic to prove its good for time/current...

No the 6mm cable feeding 9.5kw shower, albeit REF method C

 

[Richard Burns]

Ib<In<Iz

Ib is 41.3A
In is 45A
Iz is 47A

Sorted.

 

[ray-bentos]

This brings another problem to the fray which is my chosen CU only has 40 or 50amp MCBs. I know there is no requirement to provide overload protection for fixed loads but then my breaker is lower than my design current at 40amp and 50amp is above the 47amp allowed by the cable?

Alternative is to use an MK Sentry CU which has the 45amp breaker option

 

[SJD]

The 9.5kW shower is perhaps only 9.5kW at 240V, taking just under 40A. At 230V it will be a lower output? If you use a 40A MCB, I'd be surprised if it tripped.

 

[ray-bentos]

It has run fine for nearly 2 years on a 32amp MCB, its the design issues I'm worried about due to the Elecsa assessment.

 

[Richard Burns]

Either take SJD's suggestion 9.5kW @ 240V is 38A at 230V so a 40A breaker is fine.
or use an MK / Schneider CU to use a 45A MCB
Or as a shower is designed as short term load with no variation and a 40A MCB will take 41.3A for in excess of 2 hours this will not trip and cause nuisance.
The cable is protected as it can take 47A, you have short circuit protection and you are not designing a circuit where a small overload of long duration will occur. You are designing a small overload of short duration; this is permissible in the regulations, as other wise diversity calculations would not be possible. Although no diversity is permitted for showers this is a design decision that is safe and in accordance with common practice .

OK so write that down and have it available just in case the assessor should ask about your design calculations, (they very likely won't, unless they are reading this post!)

 

[KFH]

The assessors I have met are looking to pass you. You just have to make it easy for them. Make sure you have all the items on the assessment check list sorted and available. If you do not know the answer to a question do not try to bluff, just say you don't know and say where you will look it up, usually the On Site Guide. None of us, well perhaps the odd one, can remember everything.


Good luck.

 

[Prince1983]

Hi. I hope you've got some good news to share

 

[ray-bentos]

Yes got assessed yesterday, passed no worries!