Grounding of a Substation Door necessary?

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netfreak

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Dear all,

I am new to the designing field of Electrical Engineering and am pretty much enjoying my work. So currently, the project on which I am working is building a new Substation. Our client has submitted us drawings regardless of the calculation(of even a single part from Lighting to Earthing) and we although as being contractors are supposed to calculate everything and make sure that his design is alright. If not, then we propose amendments etc.

1. We have a MV Room(13.8kV maximum voltage present in the substation), in which MV Switchgear is going to be present. He has bonded the door of that entrance room to the Grounding Bar. I searched so much on the internet and in the standards but did not find any specific article referring to this particular case whether the door should be bonded or not?
I know that neglecting the bonding of door won't have much of a cost impact, but I want to stick to the standards.
2. For equipment grounding the 13.8kV MV Switchgear, 480V Switchgear, Batteries (all these three items being inside the substation in separate rooms); our Company has purchased the 120mm2 bare copper conductor in a bulk quantity and are suggesting me to use Bare Copper, instead of "Insulated". I want to confirm whether there is any standard which satisfies that using the Bare Copper Conductor for equipment bonding would be okay or should it must be insulated? Because in my opinion, any conductor coming from the Earthing Network inside the substation should be insulated and further on connecting with any electrical equipment should be insulated as well.

Please help me clarify these points whether there is any specific standard/article referring to these point?
 
All this is not usually in our wheel house, and your also in Canada.

Perhaps if you read up on UL - Canada which lists some relationship to your Code and ours?

This search used the terms " UL+canada+MV+grounding", You can also try some variable of terms in their Search!

Welcome to the Forum! :thumbsup:
 
No No, I am not in Canada. I am rather living in Saudi Arabia. I checked the Engineering Standards of here, but I did not find anything related of the standards followed in this Country.
 
This may help but it is from the NEC

250.194 Grounding and Bonding of Fences and Other
Metal Structures. Metallic fences enclosing, and other metal
structures in or surrounding, a substation with exposed electrical
conductors and equipment shall be grounded and bonded
to limit step, touch, and transfer voltages.
(A) Metal Fences. Where metal fences are located within
5 m (16 ft) of the exposed electrical conductors or equipment,
the fence shall be bonded to the grounding electrode
system with wire-type bonding jumpers as follows:
(1) Bonding jumpers shall be installed at each fence corner
and at maximum 50 m (160 ft) intervals along the
fence.
(2) Where bare overhead conductors cross the fence, bonding
jumpers shall be installed on each side of the crossing.
(3) Gates shall be bonded to the gate support post, and each
gate support post shall be bonded to the grounding electrode
system.
(4) Any gate or other opening in the fence shall be bonded
across the opening by a buried bonding jumper.
(5) The grounding grid or grounding electrode systems
shall be extended to cover the swing of all gates.
(6) The barbed wire strands above the fence shall be
bonded to the grounding electrode system.
Alternate designs performed under engineering supervision
shall be permitted for grounding or bonding of metal
fences.
Informational Note No. 1: A nonconducting fence or section
may provide isolation for transfer of voltage to other
areas.
Informational Note No. 2: See IEEE 80-2000, IEEE Guide
for Safety In AC Substation Grounding, for design and installation
of fence grounding.
(B) Metal Structures. All exposed conductive metal structures,
including guy wires within 2.5 m (8 ft) vertically or
5 m (16 ft) horizontally of exposed conductors or equipment
and subject to contact by persons, shall be bonded to
the grounding electrode systems in the area.
Click to expand...
 
mgookin said:
Is your substation utility owned or privately owned?
Click to expand...

My substation is going to be utility owned. I checked the standards of the Utility but they do not have anything mentioned specifically pointing towards the Grounding of "Doors". The only thing I found in the NEC as well was bonding the "any metallic structure/surface etc" which I assume makes my senior manager choose whether to bond or let it go, not much of a big thing to consider (I guess), since they are not taking it on a big screen.
 
There is no single item that is described by the word 'substation'.

Is this an 'open air substation' where everything is open and exposed on insulators and gravel surfaces with voltages exceeding 48kV?
Is this a 'metal enclosed substation' where all of the energized components are not exposed and the equipment is of 'tamper resistant construction?
Is in an indoor 'industrial substation' where there is some medium voltage (<48kV) connected to a close mounted transformer which is directly bussed to the LV equipment?
 
Dennis Alwon said:
This may help but it is from the NEC
Click to expand...

Thank you, thank you :)
I also have been through this. I seemed to find it noticable and wanted to ground the door but my manager did not take it into consideration and let it go. Dont know why, and nor he told me the reason.

Regarding my other question:
2. For equipment grounding the 13.8kV MV Switchgear, 480V Switchgear, Batteries (all these three items being inside the substation in separate rooms); our Company has purchased the 120mm2 bare copper conductor in a bulk quantity and are suggesting me to use Bare Copper, instead of "Insulated". I want to confirm whether there is any standard which satisfies that using the Bare Copper Conductor for equipment bonding would be okay or should it must be insulated? Because in my opinion, any conductor coming from the Earthing Network inside the substation should be insulated and further on connecting with any electrical equipment should be insulated as well.

I btw found under NEC article 250.119 that equipment grounding conductor shall be permitted to be bare, but I just want to know from you people whether this point statisfies the point to use it under my case as wel? Just want to check that I am getting the standards properly.
 
jim dungar said:
There is no single item that is described by the word 'substation'.

Is this an 'open air substation' where everything is open and exposed on insulators and gravel surfaces with voltages exceeding 48kV?
Is this a 'metal enclosed substation' where all of the energized components are not exposed and the equipment is of 'tamper resistant construction?
Is in an indoor 'industrial substation' where there is some medium voltage (<48kV) connected to a close mounted transformer which is directly bussed to the LV equipment?
Click to expand...

I do not know how to categorize it, but its an outdoor open air Substation(Building), consisting of MV Room, LV Room, Battery Room. The Transformers will be present far away and feeding the LV SWG present inside the LV Room. I hope I am clearing this? This Substation is btw going to be 13.8kV Substation.
 
Took a look at IEEE 80, NESC, and the Rural Substation Design Guide.

Couldn't find anything regarding building doors. The closest you'll get is language saying anything "likely to be energized" needs bonding. If there is a serious touch-potential risk then bond it.

That said, I don't think I've ever seen bonded doors.

There's also no requirement for bonding systems to be insulated. On the contrary: You want as many points of contact as possible.
 
netfreak said:
I do not know how to categorize it, but its an outdoor open air Substation(Building), consisting of MV Room, LV Room, Battery Room. The Transformers will be present far away and feeding the LV SWG present inside the LV Room. I hope I am clearing this? This Substation is btw going to be 13.8kV Substation.
Click to expand...

It appears you are asking about the grounding and bonding interior a to structure, where there are no internal exposed energized parts and the maximum voltage is a nominal 15kV.
But, there are exposed energized MV conductors and equipment outside of this building.

In open air substations I tend to proving bonding jumpers on doors and gates. Inside of structures with everything of 'metal enclosed construction' I tend to not bond to doors.
Almost every utility installation, I have been involved with, has had detailed grounding requirements.
 
big john said:
Took a look at IEEE 80, NESC, and the Rural Substation Design Guide.

Couldn't find anything regarding building doors. The closest you'll get is language saying anything "likely to be energized" needs bonding. If there is a serious touch-potential risk then bond it.

That said, I don't think I've ever seen bonded doors.

There's also no requirement for bonding systems to be insulated. On the contrary: You want as many points of contact as possible.
Click to expand...

Cool. Thank you big john. It feels so great to know that whatever I was reading in the NEC and understood was alright. I was just amazed to see on one side reading these things and on the other side my other LEED engineers taking these things lightly. Its a relief to come here, confirm with you people and know the correct answer technically. Thanks :)
 
jim dungar said:
It appears you are asking about the grounding and bonding interior a to structure, where there are no internal exposed energized parts and the maximum voltage is a nominal 15kV.
But, there are exposed energized MV conductors and equipment outside of this building.

In open air substations I tend to proving bonding jumpers on doors and gates. Inside of structures with everything of 'metal enclosed construction' I tend to not bond to doors.
Almost every utility installation, I have been involved with, has had detailed grounding requirements.
Click to expand...

Thank you jim. Thank you so much. Regarding the outside doors and fences, yes we are bonding them :) Regarding the internal ones, I suppose it would depend upon the mutual decision with the consultant. I appreciate your answer so much. It always gives me a heads up to have the right technical answer, even if even if people dont agree to it but still I myself feel at ease while increasing my knowledge at the same time :) Thanks :)
 
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