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Discuss Periodic Inspection Advice Please in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net

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novolts

EF Member
Hi Guys
I have just carried out a Periodic Inspection on an installation that must be at least 30 years old
I observed the following and any comments would be greatfuly received

There is an old 6 way rewire able CU when the cover is removed the supply conductors are exposed even with the switch off I was going to class this as a C1 although the cover would be considered a barrier

The main switch fuse is rated at 200A and the fuses in the main switch are 200A
The main switch supplies a buss bar chamber there are 4x63 switch fuses supplied via the bus bar chamber all fuses are rated 63A

The suppliers fuses / cutouts are rated 100A
The suppliers cable up to their cutouts is a 4x25mm SWA I have put on the observation/ comment sheet that the 4core cable is underated

And lastly there are 4 wall mounted electric heaters which supply the hot water through out the building
There is no bonding on to the supply and discharge pipework however the pipework is cross boded
kindest regards
novolts
 

Dizzy_Maskell

Electrician's Arms
It's now called an EICR rather than periodic,
Make a detailed list of all the defects and instruct the client on categories 1-3 and see what they wish to do from there.
 

novolts

EF Member
Archy
You are completely right with your comment and I would like to apologise for the above comment
I have been given EICR,s to complete 3 years after the completion of the testing and inspection course so I have forgotten some of it already no excuse but thats what happen when you work for a company that wont invest it its workforce

I am more than competent carrying the testing of circuits and I know whats good readings and whats bad readings

I did look in GN3 and found the answer to a couple of the questions I posted
so again I apologise
novolts
 

Richard Burns

Respected Member
Hi Guys
I have just carried out a Periodic Inspection on an installation that must be at least 30 years old
I observed the following and any comments would be gratefully received

There is an old 6 way rewire able CU when the cover is removed the supply conductors are exposed even with the switch off I was going to class this as a C1 although the cover would be considered a barrier
Not a problem, most CUs with the cover off will have some access to the incoming cable.Less now than formerly but still OK.

The main switch fuse is rated at 200A and the fuses in the main switch are 200A
The main switch supplies a buss bar chamber there are 4x63 switch fuses supplied via the bus bar chamber all fuses are rated 63A

The suppliers fuses / cutouts are rated 100A
The suppliers cable up to their cutouts is a 4x25mm SWA I have put on the observation/ comment sheet that the 4core cable is underated
If the suppliers fuses are 100A and the cable is capable of taking over 100A why is the cable underrated?

And lastly there are 4 wall mounted electric heaters which supply the hot water through out the building
There is no bonding on to the supply and discharge pipework however the pipework is cross boded
Is the main water incomer correctly bonded and is the exposed metalwork of the heaters earthed? If so then this is OK.

kindest regards
novolts
See my comments above.
Archy's comment was directed at Dizzy since the inspection is still a periodic inspection but the report is an electrical installation condition report.
 

novolts

EF Member
The suppliers fuses / cutouts are rated 100A
The suppliers cable up to their cutouts is a 4x25mm SWA I have put on the observation/ comment sheet that the 4core cable is underated
If the suppliers fuses are 100A and the cable is capable of taking over 100A why is the cable underrated?
Is there not a possibility of the cable overheating if the fuses in the main switch fuse are rated 2x those of the suppliers
my thoughts are 100A >80A>63A

And lastly there are 4 wall mounted electric heaters which supply the hot water through out the building
There is no bonding on to the supply and discharge pipework however the pipework is cross boded
Is the main water incomer correctly bonded and is the exposed metalwork of the heaters earthed? If so then this is OK.

Comments noted and I should sit down with a cup of tea in my hand and think it out before asking stupid questions the more testing I do the more experience I get leading to belief in myself

Badged01 I felt an apology was required if I had not made the apolpgy it would have been ignorant of me I am sorry

 

Richard Burns

Respected Member
The suppliers fuses / cutouts are rated 100A
The suppliers cable up to their cutouts is a 4x25mm SWA I have put on the observation/ comment sheet that the 4core cable is underated
If the suppliers fuses are 100A and the cable is capable of taking over 100A why is the cable underrated?
Is there not a possibility of the cable overheating if the fuses in the main switch fuse are rated 2x those of the suppliers
my thoughts are 100A >80A>63A

So the recommendation would be that the main switch fuse fuses should be down rated not that the cable is underrated.
However to gain full discrimination would be almost impossible (if you wanted any capacity on the supply).
The cables have no chance to be on overload, only on fault so will not be overheated.
In practice the arrangement that you have means the 200A fuses are redundant since if there were a short in the bus bar chamber the suppliers fuses would go first (probably) which is not an ideal arrangement, however the 63A breakers would prevent any likelihood of that happening after the bus bars.
 

novolts

EF Member
In an ideal world the suppliers cable should be rated to 200A the suppliers cutout 200A the main switch fuse 100A and the 63A left.
the company I am employed by and the companys client dont live in the ideal world
they both wait until something happens then its whose/who fault is it

thanks for advice thats why its great to be able to contact someone with a lot more experience than myself
novolts
 
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