ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by gfretwell - 03/28/24 12:43 AM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
1 members (CoolWill), 250 guests, and 13 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#99182 07/28/06 01:50 PM
Joined: Jul 2006
Posts: 20
B
bman Offline OP
Member
Got a 75KVA 480V xfmr needing to go in a tight spot. Q- clearance in 110.26 151-600v . Got my xfmr sitting across an aisle from a branch panel, the top of xfmr housing is some distance lower elevation than the bottom of branch panel with nothing on wall below panel , therefore this would not be a condition 3?(exposed on both sides) I’m supposing the key phase in 110.26 (1) is "in the direction of live parts" Also is there anything to prohibit mounting a disconnect on side of Xfmr if disc is supplied by said xfmr and meets clearance requirements?

Stay up to Code with the Latest NEC:


>> 2023 NEC & Related Reference & Exam Prep
2023 NEC & Related Reference & Study Guides

Pass Your Exam the FIRST TIME with the Latest NEC & Exam Prep

>> 2020 NEC & Related Reference & Study Guides
 

#99183 07/31/06 04:33 AM
Joined: Jul 2006
Posts: 20
B
bman Offline OP
Member
guess everbody lost their tape measures.

#99184 07/31/06 01:21 PM
Joined: Jul 2004
Posts: 9,923
Likes: 32
G
Member
It sounded like you answered your own question ... or maybe I didn't understand the question.


Greg Fretwell
#99185 07/31/06 02:08 PM
Joined: Jan 2004
Posts: 1,507
G
Member
Okay bman- I've got my ruler by my side. What do you want me to measure???
Are we talking equipment that is required to be serviced while energized? In other words if you can turn the power of and service the transformer then the clearances of Table 110.26 don't apply. See 110.26(A)
How wide is the isle?
Did you maintain the distance specified by the manufacturer of the transformer?

The only question you've posed that I can see is- Can I mount the disconnect on the transformer? My answer would be probably so as long as it would not be on a panel that has to be removed for servicing the transformer and as long as it didn't block any ventilation holes for the transformer.


George Little
#99186 08/01/06 02:46 AM
Joined: Jul 2006
Posts: 20
B
bman Offline OP
Member
Ok now were rollin. "likely to require", yep, that’s one of those phrases whose meaning changes with the AHJ mood for the particular day of the week. Always try and schedule inspection for Friday. Branch panel to me is a "likely", the xfmr ...naa, But AHJ strolls onto the job Monday morning after having shot crap on 18 holes yesterday afternoon and is gonna use me as his whippin boy, "No I don’t think so!" says he "What if you lose a phase, pop the front cover and hit the breaker to see if ya got a bad windin whilst juniors landin a #12thhn on that branch panel across the way! Haa, now you got yur self a condition 3!, move that tranny boy!" But I in my wisdom have received council from the boys at ECN, and point out that the branch panel is mounted above the horizontal plane that extends across the aisle from the top of the tranny housing so it is therefore not "in the direction of live parts" you see. Ah but wait, does "in the direction of" refer to a horizontal plane? or is it any plane, irregardless of direction? Now do you see my question?

#99187 08/01/06 06:59 PM
Joined: Jun 2002
Posts: 58
E
Member
Isn't 110.26 about providing a safe working space? And it defines the height and width of the working space. Then the table defines the depth of the working space (not a portion of it).
This one's clear, to me. 480v. is 277v to ground, and condition 3. 4 feet clear from the bottom to the top of the working space.
By the way, we're all getting panic hardware on the exit doors of our 1200A+ rooms, right?

#99188 08/02/06 02:39 AM
Joined: Jul 2006
Posts: 20
B
bman Offline OP
Member
Nope. Height only refers to "service equip., switchbds, panelbds, or MCC.

#99189 08/02/06 06:44 AM
Joined: Jan 2004
Posts: 1,507
G
Member
bman- If I read correctly your original post said you were dealing with a panelboard:
Quote
Got a 75KVA 480V xfmr needing to go in a tight spot. Q- clearance in 110.26 151-600v . Got my xfmr sitting across an aisle from a branch panel, the top of xfmr housing is some distance lower elevation than the bottom of branch panel with nothing on wall below panel , therefore this would not be a condition 3?(exposed on both sides) I’m supposing the key phase in 110.26 (1) is "in the direction of live parts" Also is there anything to prohibit mounting a disconnect on side of Xfmr if disc is supplied by said xfmr and meets clearance requirements?
so the work space of the panelboard must be provided including the depth. The transformer only needs to have clearances specified by the manufacturer and is not required to meet 110.26. I would expect that there should be access to the transformer for servicing however.

[This message has been edited by George Little (edited 08-02-2006).]


George Little
#99190 08/02/06 11:20 AM
Joined: Jul 2006
Posts: 20
B
bman Offline OP
Member
We'll leave it stand there.


Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5