NAPIT Certification Scheme Napit Electrical Installation Certificate Section 7 & 8

[newtotest]

I am really struggling with the section 7 of the Napit Installation Cert.
The reason is because the demo forms I have filled in during the course and examples elsewhere all seem to contradict eachother and it appears many people can't agree either. So by going through forums and looking at examples I have managed to confuse the issue totally and I am sure it's a very if this then that type answer, or should be.

In my situation I am going to have a main 3 phase incomer with meter and tails to a rotary isolator. This feeds a 3 phase board (DB1) with triple pole isolator main switch. From here a single phase feed is taken to DB2 via a 63Amp 60898 MCB.

My questions are if assuming I am installing circuits on DB2 are:

1 - in section 7 am I to refer to the 3 phase origin of the supply or the supply circuit to DB2. In the course I was told that the Box titled Nominal Voltage U/Uo would be 230V? That said they then said that the box Supply Protective Device would be 1361 T2 or the main fuses not the 60898 is that right?

2 - PFC and Ze in section 7 I assume would have to be taken at the 3 Phase board and recorded here.

3 - Section 8 of the same form refers to:
Main Switch / Switch Fuse / Circuit Breaker / RCD, The forms we went through had us detail this as the Main Switch of the 3 Phase Board i.e. the 60947-3 - 3 Pole - 125Amp Voltage Rating of 400V Does that sound right?

I thought I had all this right in my mind but since trying to revise and see other examples and read up it has become a complete jumble.

Any help appreciated.

 

[westward10]

What does Section 7 refer to, the supply origin details?

 

[newtotest]

It is titled "Supply characteristics and earthing arrangements". We filled this in for an initial varification on the single phase db2. Looking at in now though it seems like it's wrong because in the box we have put 1 for No of Phases and 2 for No of Wires which would refer to the subboard db2 yet right below we have filled in the Ze and the protective device as the main fuses.

 

[westward10]

It all refers to the origin, not DB2.

 

[newtotest]

Ok so tutor has led me a merry dance then and it should have been 400 v nominal, 3 phases and 4 wires in section 7 and then in section 8 what would go in there? The single phase board detail? It's also worth saying that on the test results there is this box too as attached. I take it the RCD stuff in there is only used if the supply to the board is via RCD? Thanks for helping me.

 

[westward10]

Nominal voltage (Uo) is 230v, this is the voltage between any line and earth. Section 8 refers to the origin, details for DB2 go on the schedule of test results for that DB, the rcd would only apply if it is at that board, read the top line "Characteristics at this distribution board".

 

[newtotest]

Box in sec7 is marked as U/Uo does it matter then if I write 400 or 230? And also the. Phases and wires boxes should have been 3 and 4 respectively should they?

With regard to section 8 being the origin as well is it all of section 8 or just the main switch bit as it also has the Max Demand on there?

The test results box is straight forward enough because it's clear as to what it is refering. 7 and 8 though feel muddled.

 

[westward10]

U = voltage between lines, 400v, n/a for single phase.
Uo = voltage to earth, 230v.
So nominal voltage U/Uo would be 400/230.
Section 8 is all the origin, take DB2 out of the equation.
The supply is three phase, four wire.
Put max demand as n/v.

 

[newtotest]

Great I got it I hope lol. So in simple terms.
7 is the details of the power coming in to the premises.
8 is the details of the equipment installed at the origin of the premises

And the box on the test results is where you detail the specifics of the board or perhaps boards plural that you are inspecting etc obviously using one sheet per board?

Many thanks mate your time is really appreciated.

 

[buzzlightyear]

Ok so tutor has led me a merry dance

merry dancers - Bing video - https://www.bing.com/videos/search?q=merry+dancers&view=detail&mid=14CEB139E047F8B336D514CEB139E047F8B336D5&FORM=VIRE you not one of those !

 

[newtotest]

Lol that will be me if I pass

 

[newtotest]

Just one other question . If we were to assume the certificate was not for the 3 phase board what detail would go in main switch / switch fuse / circuit breaker / RCD box in section 8? Would it be the board isolator or would it be the main fuses? And would this be the same for the first example of a cert for a sub board?