Outdoor Light Projectors & Earthing 1

[T83]

Hello,

I would like to know if somebody installs outdoor light projectors on the boundaries of their building,do they need to be earthed?
If yes,can they be earthed with the armoring of the cable or do they need an earth conductor?

Thanks

 

[rbulsara]

Yes, they need to be earthed. You can use either the cable armor (if listed for grounding conductor use) or the separate conductor.

Make sure the armor/ grounding conductor is suitably terminated to provide effective and continuous) path back to the source ground bus.

I doubt any different, but your local codes may have some say in this.

 

[waross]

Actually it depends on the local codes. For instance, the Canadian Electrical code has not allowed the cable armor of the most common cable (BX, or AC)to be used for grounding for 40 or 50 years. As the armour ages and a patina of oxidation covers the surface, the fault current tends to spiral down the armour rather than passing directly from turn to turn as when the cable is new. The impedance of the armor as a fault current path becomes unacceptably high as the cable ages.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ameeraqeel]

Defintely they need to be earthed and you can use the armour as earthing conductor if you will use an earth leakage CB 0.300 Amp. to protect persons against step and touch voltage due to earth fault current .

 

[waross]

Mindful of the differences between the CEC and the NEC, I did a little Googleing on cable armor.
What I found seems to indicate that in the USA:
The armor of type AC cable IS listed for grounding.
The armor of type MC cable IS NOT listed for grounding.
The armor of type MCAP cable IS listed for grounding.
Check your cable type and your local codes.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[davidbeach]

NEC type AC cable includes a bare grounding conductor, that's why it is allowed to be a grounding conductor. There are type MC cables that are listed as grounding conductor, but they are a continuous corrugated rather than a spiral wound armor. The spiral wound can be used in lengths up to 6 feet.

 

[waross]

Hello David;
Thanks for the clarification.
I found a fairly new configuration. It is basically MC with a bare aluminum conductor under and in contact with the armor.
It is called MC All Purpose, or MC^AP
The most accurate answer to the original question may be;-
"It depends!"

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

This thread is yet another example of why anyone asking a code question needs to state where they are and which code they are working to. Am I the only one who gets slightly irritated by this?


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If we learn from our mistakes I'm getting a great education!

 

[T83]

First of all,Thank you all for your replies!!!!Really appreciative!!

ScottyUK I am sorry for not specifying,I live in the Middle East & the projects that we take here not only in my country but other Middle Eastern countries they don't care which code you are using as long as you are using one,I know UAE follows mostly the BS,but let's say the rest don't care and the question I asked was for one of those scenarios where no code is specified & being a fresh graduate more oriented in electrical communication I am having hard times finding myself in this area of the domain,if you notice around the forum I am asking too many rookie questions hopefully with time I will become up to the level & I am in need of your guidance & experience as much of anybody else on this forum,sorry again & Thank you all!!!