NEC Required Access at Equipment. Is it ALL equipment.
NEC Required Access at Equipment. Is it ALL equipment.
(OP)
NFPA 70 requires a 30" wide x 36" deep by 78" tall clear working space in front of electrical equipment operating at <150V to ground where it is "likely to require examination, adjustment, servicing, or maintenance while energized".. (The depth is 42" for 151V-600V).
We ran into problems trying to design this large of an access for Motor Operated Valves (MOV's) on steam lines and other piping. The motor controls are mounted in the valve motor assembly, along with the myriad limit switches, torque switches and accessories used to operate the valve. The problem is the valve location in pipe racks and pipe runs makes providing this space problematic.
How do you comply with this? Some options:
Have a policy of no work on the valve unless it is de-energized?
Place a disconnect immediately adjacent to the valve to make it easier to de-energize?
Spend the significant extra money to route the 16" steam line to a location where access is available? (Plus adding the steam traps and drains needed).
Provide "reasonable" access for connecting and repairing, but not the full 30" x 42" x 78" space?
These control enclosures are not a panel with a swing door and a well defined "front" access space. Most MOV controls are ultra compact and are crammed under a round cover with access to terminals from all directions. The motor and enclosure are usually mounted so we get to straddle the pipe to work on it.
Most installations that I've seen have OK access, a few are terrible, and a few meet the letter of the code. What is your experience.
We ran into problems trying to design this large of an access for Motor Operated Valves (MOV's) on steam lines and other piping. The motor controls are mounted in the valve motor assembly, along with the myriad limit switches, torque switches and accessories used to operate the valve. The problem is the valve location in pipe racks and pipe runs makes providing this space problematic.
How do you comply with this? Some options:
Have a policy of no work on the valve unless it is de-energized?
Place a disconnect immediately adjacent to the valve to make it easier to de-energize?
Spend the significant extra money to route the 16" steam line to a location where access is available? (Plus adding the steam traps and drains needed).
Provide "reasonable" access for connecting and repairing, but not the full 30" x 42" x 78" space?
These control enclosures are not a panel with a swing door and a well defined "front" access space. Most MOV controls are ultra compact and are crammed under a round cover with access to terminals from all directions. The motor and enclosure are usually mounted so we get to straddle the pipe to work on it.
Most installations that I've seen have OK access, a few are terrible, and a few meet the letter of the code. What is your experience.






RE: NEC Required Access at Equipment. Is it ALL equipment.
Most inspectors consider NEC Section 110.26 "likely to require examination, adjustment, servicing, or maintenance while energized" to be line voltage and required intervention regularly such as fused switches, etc. Generally I've seen controls being overlooked, but there isn't anything in black and white. You need to consult with the local authority having jurisdiction regarding how they interpret the requirement.
Ron
RE: NEC Required Access at Equipment. Is it ALL equipment.
RE: NEC Required Access at Equipment. Is it ALL equipment.
If there is no need to service the equipment WHILE ENERGIZED, then the clearance issues are not applicable. So if, for example, the equipment is a motor, and you cannot normally service the motor while energized (hence a LO/TO requirement), this does not apply. So I can only imagine that MOVs would follow that rule; you must disconnect and lock out the power prior to opening any live electrical areas of it.
Whether or not, in practice, someone chooses to VIOLATE that LO/TO rule whether out of disregard or necessity, that does not mean you must DESIGN the access space require for that.
"Will work for (the memory of) salami"
RE: NEC Required Access at Equipment. Is it ALL equipment.
RE: NEC Required Access at Equipment. Is it ALL equipment.
I seen, tested and set limits on MOVs in the most difficult places. Sometimes it took scafolding, ladders etc to access the valves. Teh people who design piping systems don't usually design to NFPA anything.
If it's a powerplant your working on the NEC doesn't necassarly apply.