12,470/7,200 3ph 4wire Service Switch gear Working space

Z

zemingduan

Senior Member
Location
Philadelphia,PA
Occupation
Electrical Designer
The electrical service from the utility company (Atlantic City Electric) is 12,470/7,200 V 3ph 4wire. We have a 15KV switch gear and then substations transformer to power the building.

I got the minimum 6' required working space from NEC NEC 2020 table 110.34 (A) for the switchgear. But the ACE engineer request at least 8 ft clearance in front of the switchgear. He states that to change the 12kv fuses by a qualified electrician, they would use an 8 ft hot stick so the 6 ft clearance is not enough. Is this true? I mean this is not listed in their handbook or NEC. I would like to here some thoughts from you. Thanks!

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zemingduan said:
mean this is not listed in their handbook or NEC. I would like to here some thoughts from you
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The table minimums are what required. Why condition 3? Regardless of the length of the stick if this were condition 1 with a sheetrock wall you only need 4'.
 
8’ isn’t enough to work an 8’ stick.
I would require at least 10’ IF WE OWNED THE SWITXHGEAR.

Who owns the switchgear? ACE?
If not the ACE engineer has no say
 
Hv&Lv said:
Who owns the switchgear? ACE?
If not the ACE engineer has no say
Click to expand...
Some utilities do the switching and fuse removal on customer owned gear, when the customer does not have qualified people on site and there is a cold sequence utility metering section in the lineup. In these cases i would expect the POCO manual to include the required clearance.

edit to fix spelling.
 
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jim dungar said:
Some utilities do the switching and fuse removal on customer owned gear, when the customer does not have qualified people on site and there is a cold sequence utility metering section in the lineup. In these cases i would expect the POCO msusl to include the required clearance.
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We have one place we handle the fuses on a 14,400 site. More or less a favor for the business owner. We service their cap bank also. They buy the parts.
We made them build their fence with 10’ clearance and made them have the fence opening facing the switchgear door.
If we are responsible, then it’s going to be our way or no way.
If ACE takes that responsibility then the electrician has little choice but to make the clearance like ACE wants it, IMO
 
Hv&Lv said:
We have one place we handle the fuses on a 14,400 site. More or less a favor for the business owner. We service their cap bank also. They buy the parts.
We made them build their fence with 10’ clearance and made them have the fence opening facing the switchgear door.
If we are responsible, then it’s going to be our way or no way.
If ACE takes that responsibility then the electrician has little choice but to make the clearance like ACE wants it, IMO
Click to expand...

jim dungar said:
Some utilities do the switching and fuse removal on customer owned gear, when the customer does not have qualified people on site and there is a cold sequence utility metering section in the lineup. In these cases i would expect the POCO manual to include the required clearance.

edit to fix spelling.
Click to expand...

Thanks everyone for the information! The switchgear is customer owned but ACE has specific requirements about it. The ACE handbook has wording " The Company shall always be consulted regarding the location, layout and key design features of customer owned substations before the plans are completed."

The ACE engineer requests min 8' clearance. I questioned ACE engineer the requirements by reference the NEC table yesterday and just got the response. He insists "At least 8' clearance to safely allow an electrician to replace fuses the only approved method is using an 8 ft hookstick". After all NEC table is minimum requirements we will have to follow ACE's requirements and enlarge the electrical room.
 
zemingduan said:
At least 8' clearance to safely allow an electrician to replace fuses the only approved method is using an 8 ft hookstick".
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If that's their rule then it's not the same as what's required by the NEC. Are they saying that someone would replace the fuses while the equipment is energized?
 
infinity said:
If that's their rule then it's not the same as what's required by the NEC. Are they saying that someone would replace the fuses while the equipment is energized?
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I think so. I think the medium voltage technician will need to replace the fuses while energized without cut off the power for the whole building. The working space required by NEC is also the space for serving the equipment while energized, right?

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