NEC 2020 Changes that could increase live to live working distances

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Michele

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Massachusetts
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Electrical Designer
We are planning a new electrical room with feeds to handle a small Control Building with a small Control Room and a few offices. The electrical room is adequate in size presently but designed to the 2017 code. Do you see changes in the 2020 code that would increase live to live working distances? We may need to increase the size of our electrical room. Thank you.
 
Roger wrote a reply but I do not see it in this thread. Understood Roger. Live to live is prohibited. I am speaking in general terms. A coworker received an ECM article, that I have yet to read, indicating electrical rooms may start increasing in size due to changes in the 2020 code. I am not referring to a specific live to live but in general the equipment spacing requirements.
 
You are correct I removed my post. I am not up to speed with the 2020 yet and was not sure my reply was on target.

Roger
 
There is a rule that could impact the size of the electrical room. 110.26(C)(2) has been modified and will have a huge impact where "large equipment" is installed across the aisle from other electrical equipment. The impact of the rule is that where you have an enclosure door open, you must have at least 24" between the door and the other equipment to provide an egress path.
110.26(C)(2) Large Equipment. For large equipment that contains overcurrent devices, switching devices, or control devices, there shall be one entrance to and egress from the required working space not less than 610 mm (24 in.) wide and 2.0 m (6'/2 ft) high at each end of the working space. This requirement shall apply to either of the following conditions:
(1) For equipment rated 1200 amperes or more and over 1.8 m (6 ft) wide
(2) For service disconnecting means installed in accordance with 230.71 where the combined ampere rating is 1200 amperes or more and over 1.8 m (6 ft) wide
Open equipment doors shall not impede the entry to or egress from the working space.
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Does this mean that if you have two mcc line-up facing each other you have to account for both door swings open at the same time and the extra 24 inches for egress? So for example , both doors are 20 inches wide, you would need a total clearance of 20+20+24=64 inches This would be more than the required working space from table 110.26(A)(1) condition 3 gives me 48 inches.
 
Tim Davies said:
Does this mean that if you have two mcc line-up facing each other you have to account for both door swings open at the same time and the extra 24 inches for egress? So for example , both doors are 20 inches wide, you would need a total clearance of 20+20+24=64 inches This would be more than the required working space from table 110.26(A)(1) condition 3 gives me 48 inches.
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Yes, either or both of the MCC's would have to fit the definition of "Large Equipment" - 1200 amperes or more and over 1.8 m (6 ft) wide
 
ron said:
Yes, either or both of the MCC's would have to fit the definition of "Large Equipment" - 1200 amperes or more and over 1.8 m (6 ft) wide
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I can see some redesigns coming on small projects to use 1000A bus or less, where people often put in 1200A and up just to cover future growth....

But as of July1, only Massachusetts, Colorado, Wyoming and S. Dakota have adopted the 2020 code. Being that you (Michele) are in Mass., it will apply to you.
NECInEffect7120.ashx
 
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I always figured the six foot rule assumed ONE door is open at a time. If you read this rule from the perspective of either side it’s 44” (20+24”) on MCC.
 
Jraef said:
I can see some redesigns coming on small projects to use 1000A bus or less, where people often put in 1200A and up just to cover future growth....

But as of July1, only Massachusetts, Colorado, Wyoming and S. Dakota have adopted the 2020 code. Being that you (Michele) are in Mass., it will apply to you.
NECInEffect7120.ashx
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We have resorted to bolt on covers for front/rear accessible SWBDs and SWGR where normally it would have been hinged (where it makes sense). Nothing we can do about rackable breakers, but for doors only, we have to compromise on what will ultimately piss-off the staff for ease of access.
I've asked our manufacturers reps to consider 180 deg door hinges be available
 
Does anyone have access to the NEC code handbook, that might explain the "open equipment door" line in more detail?
 
I don't get the map showing illinois as green. Chicago has its own electrical code and the rest of the state does its own thing. They can be on whatever version of the code the local authorities decide on or no code at all in some places, but there is no statewide code requirement.
 
petersonra said:
I don't get the map showing illinois as green. Chicago has its own electrical code and the rest of the state does its own thing. They can be on whatever version of the code the local authorities decide on or no code at all in some places, but there is no statewide code requirement.
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According to Mike Holt:
“The state (Illinois) adopted the 2008NEC statewide effective July 1, 2011 for non-building code jurisdictions.”

Does this mean that any area without a building code is required by the state to follow 2008? Of course if there’s no building code, there won’t be any inspectors, either!
 
retirede said:
According to Mike Holt:
“The state (Illinois) adopted the 2008NEC statewide effective July 1, 2011 for non-building code jurisdictions.”

Does this mean that any area without a building code is required by the state to follow 2008? Of course if there’s no building code, there won’t be any inspectors, either!
Click to expand...
I would want to see a citation of the law that was passed to do this. There is no state wide body that has this authority as far as I know.
 
retirede said:
According to Mike Holt:
“The state (Illinois) adopted the 2008NEC statewide effective July 1, 2011 for non-building code jurisdictions.”

Does this mean that any area without a building code is required by the state to follow 2008? Of course if there’s no building code, there won’t be any inspectors, either!
Click to expand...
Yes, it means that if there is no local building code the 2008 NEC applies. If you have a local code, it can be any edition. I believe there is at least one on the 93 or 96 in Illinois.
There is not much way to enforce it in an area that does not have local codes.
 
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