Three phase with neutral....earthing ..?

[Greatwhiteshark]

Hi everyone.

please comment on the earthing of three phase as a new installation .
Then are you allowed to use the armour or not and what is the Regulations about earthing when there is a cable with 4 core but you need a neutral and a earth plus the 3phase..?

Many thanks

M0LVW:dizzy2:

 

[Darkwood]

Your profile gives you as both domestic and Industrial, this is not a question an industrial electrician would ask to be honest in the broad context you put it, are you on about a specific size here?.. in answer to your question it depends on a few factors here, the size and type of SWA you require, what its been used for and if the equipotential bonding requirements of the install are been extended through the SWA.

More info is needed here, do you have a copy of the regulations so we can point you in the right direction here?

 

[davesparks]

Whether it's as a new installation or an existing one the earthing will generally be achieved by burying a load of metal in the ground and connecting it to the star point.

As far as using the armour as a cpc goes you need to calculate its suitability using the adiabatic equation

 

[Farmelectrics]

more info required for you to get the right advice

 

[Greatwhiteshark]

Hi there

thanks for your info could you let me know where I can get more info on that a diabetic equation please .

many thanks

kind regards

 

[telectrix]

its in the bible. (BS7671).

 

[Greatwhiteshark]

Your profile gives you as both domestic and Industrial, this is not a question an industrial electrician would ask to be honest in the broad context you put it, are you on about a specific size here?.. in answer to your question it depends on a few factors here, the size and type of SWA you require, what its been used for and if the equipotential bonding requirements of the install are been extended through the SWA.

More info is needed here, do you have a copy of the regulations so we can point you in the right direction here?[/QUOTE

yes I have a copy

 

[Greatwhiteshark]

Hi Mr Darkwood
i want to know what the regulations state about Armour earthing over all..... or could some one direct me to the correct paragraph in the regs. That explain armour Earthing and bonding ....I have my own regs copy.

As I understand it is a forum for Questions so I don't see what my profile have to do with the Question .

Many thanks

enjoy your day

regards

 

[telectrix]

adiabatic ..... S = √( I² x t)/k

 

[Greatwhiteshark]

Yep I know but where and what paragraph please .

 

[telectrix]

Hi Mr Darkwood
i want to know what the regulations state about Armour earthing over all..... or could some one direct me to the correct paragraph in the regs. That explain armour Earthing and bonding ....I have my own regs copy.

As I understand it is a forum for Questions so I don't see what my profile have to do with the Question .

Many thanks

enjoy your day

regards

for most application the armour of SWA up tp 95mm is adequate as a cpc. it might not be adequate for a bonding conductor.

 

[Greatwhiteshark]

Thanks

could you let me know where in the regs I can find it please? And could you give me a example please .

thanks

 

[Greatwhiteshark]

Many thanks.

 

[derek]

http://www.electriciansforums.co.uk...ons/28128-example-use-adiabatic-equation.html

 

[Darkwood]

Hi Mr Darkwood
i want to know what the regulations state about Armour earthing over all..... or could some one direct me to the correct paragraph in the regs. That explain armour Earthing and bonding ....I have my own regs copy.

As I understand it is a forum for Questions so I don't see what my profile have to do with the Question .

Many thanks

enjoy your day

regards

It wasn't a dig, it was maybe the way you phrased the question and an unusual question to ask from an Industrial Electrician, usually the question is more specific to a size and core number and whether the armour's CSA is adequate, you ask such a broad question it is covered by numerous regulations and subject to application that we cannot just give you a straight answer or guide you to a specific regulation.

If you are asking if the armour can be used as the earth then it can be see (543.2.1), whether you can use the armour as an earth is subject to the specifics of the SWA, the specifics of the use of the SWA (E.G. -If its a submain and equipotential bonding is needed locally then additional earth may be needed).

Whatever you calculate as the requirements and whether the armour meets your needs as an earth or not, its still required to be earthed even if not used as the earth.

There is a table of core count and cable size that shows what cables fall within the CSA requirements to allow for use as a circuit earth conductor I'll try locate a copy for you.

 

[Darkwood]

Note this is for 70c SWA's thermoplastic

Note - below is for 90c XPLE cables

 

[Greatwhiteshark]

Thanks so much that's great info .will definitely make good use of it I was not sure about using the armoured in those different ways I know it must be earthed always but now I will study that part of the regs a bit more.

great help

thanks

kind regards

 

[Greatwhiteshark]

Brilliant thanks ..