commercial installs

[atm84]

May seem like a stupid question but I have come across a number of commercial installs such as offices, sports centres etc where the installer has used steel conduit which is embedded into the building fabric. As a result rcd's/rcbo's are not generally required on the lighting circuits.

I'm trying to work out why they wouldn't just plaster over the cables and fit an RCD or rcbo to the circuit. Surely it would be cheaper than using steel conduit everywhere.

The only reasoning that I can think is that if that there would be much less disruption caused if someone drilled through a cable and also by not fitting an RCD/rcbo it alleviates the problem of nuisance tripping.

 

[ipf]

It's all about working to specification. The ideal installation is to be done in steel conduit, embedded. Can't get much better.

 

[atm84]

Why though?

 

[Clive P]

Hi,

Architects specification.

Regards.

 

[ipf]

Public or important buildings in many instances. Look at hospitals, fire stations, SPORTS CENTRES, etc. As few problems as possible and the safest installation are required.

 

[driverman]

As it's a commercial building RCD's RCBO's are not reqd. Assuming all other criteria met. Or have i got this wrong?

 

[ipf]

As it's a commercial building RCD's RCBO's are not reqd. Assuming all other criteria met. Or have i got this wrong?

Most specifications will insist on RCD protection for general socket outlets, at least.

 

[atm84]

Driver man that's correct however like Ipaf says socket outlets used for portable appliances up to 20amps require RCD protection. Lighting circuits and such like are omitted from RCD protection if the installation is under the control of skilled and competent persons ie a maintenance guy. My point is why not just fit an RCD and not have to bother installing conduit.?

 

[atm84]

Hi,

Architects specification.

Regards.

What do architects know? They usually don't know the difference between a plug and a socket. The amount of times I had heard then say 'I want two plugs fitting over there', 'oh you mean two sockets' I say.

 

[Clive P]

Hi,

I have worked with some very good Architects and not trying to question your thoughts but any good spark would know the answer to the question you are posting, and would regard that type of installation to be one of the best for a lot of good reasons.

Regards.

 

[snowhead]

To the O.P
In a house then why not just clip flex on top of the plaster?
Why bother hiding it.

Why do they use doors costing over £1k in some commercial buildings when a B&Q £30 special would still fill the hole?

 

[Lukethoma1985]

Saves nuisance tripping due to the rcd

 

[Plonker 3]

Nuisance tripping only occurs on a shared RCD board. RCBOS will only trip when there is a fault on the circuit.

 

[atm84]

Hi,

I have worked with some very good Architects and not trying to question your thoughts but any good spark would know the answer to the question you are posting, and would regard that type of installation to be one of the best for a lot of good reasons.

Regards.

Must make me a bad spark then.

 

[atm84]

Hi,

I have worked with some very good Architects and not trying to question your thoughts but any good spark would know the answer to the question you are posting, and would regard that type of installation to be one of the best for a lot of good reasons.

Regards.

Not best price though ad I am sure you are aware In this day the cost of an installation is one of the major factors that determines the type of install. I'm not asking of justification I was looking for reasoning why steel conduit may be better not just cos some architect specs it. I was looking for reasons why anyone would spec it.
Thanks for your help guys.

 

[atm84]

(null)

Not quite the same is it. Now you are being silly aren't you.

Flex would be visible wouldn't it you silly boy. Customers don't want to see cable clipped surface.

In OP the cabling is hidden, nobody would see it I'm asking what benefits would there be if steel conduit was used.

PS I'm sure the fire regs may pay an important factor regarding the type of door.

 

[ipf]

Nuisance tripping only occurs on a shared RCD board. RCBOS will only trip when there is a fault on the circuit.

Could be even more of a nuisance though:thinking2:

 

[Lou7]

Conduit is rewireable.

 

[Lukethoma1985]

I know, what i mean is if theres a faulty washer or dryer etc it wont knock that circuit off just for a faulty appliance

 

[atm84]

Conduit is rewireable.

Cheers Lou

 

[Engineer54]

May seem like a stupid question but I have come across a number of commercial installs such as offices, sports centres etc where the installer has used steel conduit which is embedded into the building fabric. As a result rcd's/rcbo's are not generally required on the lighting circuits.

I'm trying to work out why they wouldn't just plaster over the cables and fit an RCD or rcbo to the circuit. Surely it would be cheaper than using steel conduit everywhere.

The only reasoning that I can think is that if that there would be much less disruption caused if someone drilled through a cable and also by not fitting an RCD/rcbo it alleviates the problem of nuisance tripping.

Obviously these installations are outside of your experience of house bashing. These installations are as you say ''Commercial'' so one expects ''More'' than what you would see installed in an average domestic installation. For a start most decent sized commercial call for and merit a wiring system that is rewirable, and a higher standard of integral safety. Putting everything down to the lowest cost, doesn't work too well, where members of the public are using such facilities with insurance companies.
Apart from anything else, most high end commercial projects, will come with a fully spec'd installation contract, and i can assure you those spec's wouldn't include plastered over T&E cables!!!


As for thinking that all Architects are dummies, and don't know what they're talking about, then you couldn't be more wrong. Many of them know more about the requirements of electrical installations (as well as all the other services) in buildings than you. Few people realise a RIBA architect has studied his profession for a minimum of 7 years to gain that RIBA status!!

 

[shanky887614]

Obviously these installations are outside of your experience of house bashing. These installations are as you say ''Commercial'' so one expects ''More'' than what you would see installed in an average domestic installation. For a start most decent sized commercial call for and merit a wiring system that is rewirable, and a higher standard of integral safety. Putting everything down to the lowest cost, doesn't work too well, where members of the public are using such facilities with insurance companies.
Apart from anything else, most high end commercial projects, will come with a fully spec'd installation contract, and i can assure you those spec's wouldn't include plastered over T&E cables!!!


As for thinking that all Architects are dummies, and don't know what they're talking about, then you couldn't be more wrong. Many of them know more about the requirements of electrical installations (as well as all the other services) in buildings than you. Few people realise a RIBA architect has studied his profession for a minimum of 7 years to gain that RIBA status!!

it does not matter if the architect knows f all about electrics because its likely they will have electrical and mechanical advisors.

never seen a bit of twin in comercial its usually singles in trunking/flex on tray then conduit of shoots, don't take my word for it as mainly do bms.

spent 6 months on one job in a hospital and was all flex/singles etc on tray and plastic conduit.


you use whats in the spec, for example some places specify swa for everything but others we use sy

 

[Engineer54]

it does not matter if the architect knows f all about electrics because its likely they will have electrical and mechanical advisors.

never seen a bit of twin in comercial its usually singles in trunking/flex on tray then conduit of shoots, don't take my word for it as mainly do bms.

spent 6 months on one job in a hospital and was all flex/singles etc on tray and plastic conduit.


you use whats in the spec, for example some places specify swa for everything but others we use sy

As does our Architect, but that certainly doesn't mean he doesn't know what he's talking about in his own right!! lol!!

I don't doubt it either, the high standards that British electrical installations used to be known for, is fast going down hill all the time from what i can make of it.

In contrast, on my present (and past) hospital projects, the vast majority of the BMS control wiring is within metallic containment systems (trunking and conduit)...

 

[atm84]

Many thanks for your assistance guys. Engineer54 for your information I used to work as an electrician working on many commercial installations. Just because someone works on an installation it doesn't mean that they know WHY everything is done in a particular way. I have met many sparks who just do as they are told and do not question why it is done.

 

[shanky887614]

As does our Architect, but that certainly doesn't mean he doesn't know what he's talking about in his own right!! lol!!

I don't doubt it either, the high standards that British electrical installations used to be known for, is fast going down hill all the time from what i can make of it.

In contrast, on my present (and past) hospital projects, the vast majority of the BMS control wiring is within metallic containment systems (trunking and conduit)...

only in plantrooms usually though, if they can get away with it they will use plastic conduit as most is only 24v outside plantrooms

 

[THE INVERTER]

Rewire-able option at a later date is also an option

 

[atm84]

Cheers inverter. However how many commercial installs do you actually come across that are rewired and the original conduit is left in place. Normally any where that needs re wiring is being refurbished and all the conduit is being ripped out.

 

[shanky887614]

Cheers inverter. However how many commercial installs do you actually come across that are rewired and the original conduit is left in place. Normally any where that needs re wiring is being refurbished and all the conduit is being ripped out.

true that.

or thwy put in new conduit next to old and leave it in

 

[telectrix]

true that.

or thwy put in new conduit next to old and leave it in

if it was copper they wouldn't leave it.

 

[shanky887614]

if it was copper they wouldn't leave it.

your right there tel