Church conversion to domestic from commercial Help

[awp_electrical]

Hello all,

I have been asked to check over a converted church which has already been converted to offices. My client wants to convert it to a domestic dwelling.

They have 4 old square d DB, 2 are for all circuits and 2 are for off peak night storage heaters.

My question is .... as It was commercial TT 3ph installation the lack RCD protection in the kitchens and bathrooms doesn't concern me due to the age of the installation. Now its for domestic though, should I be recommending replacing the very dated square d boards for more modern RCD protected DB ?

These square D boards isolation switches appear to be a single plastic boated bar in black rather than the modern 3 plastic switches joined. Hope that makes sense.

any thought would be great.

Kind regards

Andy

 

[Engineer54]

Words fail me!!

 

[awp_electrical]

Words fail me!!

Please enlighten me why words fail you
its quite straight forward. The original installation was pre 16th edition regs and commercial. All I have asked is would you recommend replacing the old DB as the premises have changed to domestic from commercial for added protection for the client.

quite a simple question really

 

[Rockingit]

Turning your question around a little:

You're going to be having to do both adaptive and new works in order to transform it into the finished project.....so you'll need to do that in compliance with 17th.....which means you'll be needing RCD protection.....which means the easiest/most cost effective way of achieving that is by ripping anything out that doesn't comply with your new design. Like old CU's, for example.

 

[Richard Burns]

Please confirm that you are assessing an existing installation that has a TT earthing system and no RCD protection?

 

[dingledong]

If it was a simple question really,then why ask it ?

 

[awp_electrical]

Actually reading my initial line of questioning back it does look a little weird.

I have not been instructed too rework any circuits in any special locations but simply to advise if possible if the system should be converted to a domestic setup from a commercial installation. Which as you rightly point out would need stripping out and starting again or just leave it as is and just recommend protection to the 3 circuits feeding the locations of concern.

Yes the system is TT and it does not currently have RCD protection.

I am only asking ( and poorly too ) as you guys have considerably more experience with commercial than I do for sure.

Never been asked to check a commercial system with express wishes to change for domestic use.

sorry again for my poorly worded initial question.

 

[awp_electrical]

If it was a simple question really,then why ask it ?

I only ask because , as I tutors used to say " if you have any doubts about anything at all then seek advise from time served "

 

[awp_electrical]

Please confirm that you are assessing an existing installation that has a TT earthing system and no RCD protection?

Actually reading my initial line of questioning back it does look a little weird.

I have not been instructed too rework any circuits in any special locations but simply to advise if possible if the system should be converted to a domestic setup from a commercial installation. Which as you rightly point out would need stripping out and starting again or just leave it as is and just recommend protection to the 3 circuits feeding the locations of concern.

Yes the system is TT and it does not currently have RCD protection.

I am only asking ( and poorly too ) as you guys have considerably more experience with commercial than I do for sure.

Never been asked to check a commercial system with express wishes to change for domestic use.

sorry again for my poorly worded initial question.

 

[Richard Burns]

What is the Ra / Ze?
If there is no RCD protection on a TT installation and the Ra is not in the TN levels then I would recommend that you ask the customer to ensure the installation is isolated at the earliest opportunity as it could be deadly in the case of a fault.

 

[trev]

I only ask because , as I tutors used to say " if you have any doubts about anything at all then seek advise from time served "

Is it not the job of training mentors to make sure that a trainee knows what he or she is doing?
This line is a cop out, if I were you I'd ask for my money back from the Electrical Trainee factory.
There's a difference between having a head scratching moment and not having a clue about something pretty basic.

 

[Adam W]

What is the Ra / Ze?
If there is no RCD protection on a TT installation and the Ra is not in the TN levels then I would recommend that you ask the customer to ensure the installation is isolated at the earliest opportunity as it could be deadly in the case of a fault.

Would a TT not require RCD protection anyway?

 

[Richard Burns]

Would a TT not require RCD protection anyway?

411.5.2 One or more of the following types of protective device shall be used, the former being preferred:
(i) An RCD
(ii) An overcurrent protective device.
NOTE 1: An appropriate overcurrent protective device may be used for fault protection provided a suitably low value of Zs is
permanently and reliably assured.
NOTE 2: Where an RCD is used for fault protection the circuit should also incorporate an overcurrent protective device in
accordance with Chapter 43.

Obviously the additional protection from 30mA RCDs is still required even if the Ze is low.

 

[UNG]

Actually reading my initial line of questioning back it does look a little weird.

I have not been instructed too rework any circuits in any special locations but simply to advise if possible if the system should be converted to a domestic setup from a commercial installation. Which as you rightly point out would need stripping out and starting again or just leave it as is and just recommend protection to the 3 circuits feeding the locations of concern.

Yes the system is TT and it does not currently have RCD protection.

I am only asking ( and poorly too ) as you guys have considerably more experience with commercial than I do for sure.

Never been asked to check a commercial system with express wishes to change for domestic use.

sorry again for my poorly worded initial question.

You need to ask yourself is this job taking you out of your depth and beyond your capabilities if this is the case you really need to pass this job to someone with necessary knowledge and experience. The difficulty with answering any question on here is the lack of information provided as we don't have a crystal ball view of the site to fill in the missing information or pertinent facts that may affect the final solution

I only ask because , as I tutors used to say " if you have any doubts about anything at all then seek advise from time served "

Where / are your tutors not time served do they not offer a guarantee to answer any questions that were not covered in your course

Sorry to be negative but safety has to be of prime concern and your tutors abdicating their responsibility to the "time served" in some ways shows their lack of ability, knowledge and understanding of the courses they are teaching and providing certificates for and the implications this has for the general public and customers you are working for