ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by tortuga - 03/28/24 05:57 PM
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
0 members (), 260 guests, and 19 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Oct 2000
Posts: 4,116
Likes: 4
Member
From the 'Mailbag'
Quote
I have installed a 7 1/2 ton split system air conditioning unit in an electrical/communication room. It is 460 V 3 phase. According to the UMC I need to have a 30" X 30" clear access for where the power is tied into the unit and for controls. I have an inspector who is saying that I must go by the NEC and have 30" X 42" clear access, due to the voltage. Can you help me out.
Thanks


Bill
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
 

Joined: Dec 2000
Posts: 4,294
Member
Your inspector is correct if you have a grounded surface on the opposite side of the workspace.
NEC 110-16 deals with working clearances.
Table 110-16(a) gives the working clearances as they apply do different situations.
At 151-600V to ground, the clearances are:
1)No live or grounded parts on other side=3'
2)Grounded parts on the other side=3-1/2'
3)Live parts on both sides=4'

In any case, the 30" in the UMC is not sufficient by NEC, as the requirement at 0-150V is 3' in any of the conditions mentioned above.


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