Working Clearance for Class 2 24V circuit

[donburde]

I have a situation where VAV heat coils are heated with water and there is a solenoid that opens and closes regulating the flow of hot water water. The EOR is telling me that I need to have 36" working space in front of the access panel that houses the solenoid based on 110.26(A)(1). This class 2 power limited circuit is free-wired to the VAV and entering the VAV box with a cord connector.

 

[petersonra]

725.3

 

[donburde]

725.3

There isn't anything in at article about working clearances. Is your implication that since there is not, 110.26(A)(1) would not apply to this?

 

[kwired]

110.26 is so vague that it can be applied to almost anything, yet there is many things pretty common that almost never meet the requirements in that section.

Luminaire on a high ceiling - are we supposed to have a working platform that meets 110.26 requirements for every luminaire?

Junction boxes in crawl spaces? Aren't they "likely to require examination, adjustment, servicing, or maintenance while energized" when troubleshooting? Yet we encounter them all the time.

Most AHJ's typically limit applying this to panelboards, switchboards or overcurrent devices other than certain supplementary type devices, motor control centers but not necessarily all motor controllers as a general rule, and other industrial control panel types of equipment.

 

[paulengr]

110.26 is so vague that it can be applied to almost anything, yet there is many things pretty common that almost never meet the requirements in that section.

Luminaire on a high ceiling - are we supposed to have a working platform that meets 110.26 requirements for every luminaire?

Junction boxes in crawl spaces? Aren't they "likely to require examination, adjustment, servicing, or maintenance while energized" when troubleshooting? Yet we encounter them all the time.

Most AHJ's typically limit applying this to panelboards, switchboards or overcurrent devices other than certain supplementary type devices, motor control centers but not necessarily all motor controllers as a general rule, and other industrial control panel types of equipment.

The reasonable standard that I see used for whether or not something needs an arc flash sticker is annual maintenance. So for instance changing 100 W incandescent light bulbs meets the 1 year requirement since they usually don’t last that long but fluorescent and LED easily do. Most motor peckerheads aren’t accessed annually or more often but an MCC or panelboard in an industrial plant usually is. In residential probably nothing requires frequent maintenance except the circuit breaker for a teenage girls bathroom receptacle.!I know 110.26 does not say this though.

It’s one of those interpretation things where you get the usual over/under zealous inspection problems subject to the whims of the inspector. But if you apply the “frequent maintenance” standard it becomes pretty obvious where it should apply.

 

[don_resqcapt19]

The problem is Table 110.26(A) as it starts at ZERO voltage. There have been public inputs to change this to 50 volts to better match up with NFPA 70E, but so far such PIs have been rejected.

 

[kwired]

The reasonable standard that I see used for whether or not something needs an arc flash sticker is annual maintenance. So for instance changing 100 W incandescent light bulbs meets the 1 year requirement since they usually don’t last that long but fluorescent and LED easily do. Most motor peckerheads aren’t accessed annually or more often but an MCC or panelboard in an industrial plant usually is. In residential probably nothing requires frequent maintenance except the circuit breaker for a teenage girls bathroom receptacle.!I know 110.26 does not say this though.

It’s one of those interpretation things where you get the usual over/under zealous inspection problems subject to the whims of the inspector. But if you apply the “frequent maintenance” standard it becomes pretty obvious where it should apply.

This thread is not about arc flash stickers though.

I don't think NEC uses "frequent maintenance" as a standard term either.

So as is 110.26 is still pretty vague and very open to interpretation.

 

[paulengr]

This thread is not about arc flash stickers though.

I don't think NEC uses "frequent maintenance" as a standard term either.

So as is 110.26 is still pretty vague and very open to interpretation.

Look back a few sections. This is not a 70E thing,


110.16 Arc-Flash Hazard Warning. Electrical equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers in other than dwelling units that are likely to require examination, adjustment, servicing, or maintenance while energized must be marked to warn qualified per- sons of the danger associated with an arc flash from short circuits or ground faults. The marking can be made in the field or the factory, but it must meet the requirements of 110.21(B), and be clearly visible to qualified persons before they examine, adjust, service, or perform maintenance on the equipment.

It uses the word “likely”. This is the one that gets interpreted as “frequently” because otherwise everything needs a sticker especially because the 70E boneheads can’t get it that arc flash doesn’t happen below around 200 V.

 

[kwired]

Look back a few sections. This is not a 70E thing,


110.16 Arc-Flash Hazard Warning. Electrical equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers in other than dwelling units that are likely to require examination, adjustment, servicing, or maintenance while energized must be marked to warn qualified per- sons of the danger associated with an arc flash from short circuits or ground faults. The marking can be made in the field or the factory, but it must meet the requirements of 110.21(B), and be clearly visible to qualified persons before they examine, adjust, service, or perform maintenance on the equipment.

It uses the word “likely”. This is the one that gets interpreted as “frequently” because otherwise everything needs a sticker especially because the 70E boneheads can’t get it that arc flash doesn’t happen below around 200 V.

I don't disagree but that is not topic of OP, question was about working clearances not warning labels.

 

[tortuga]

I have a situation where VAV heat coils are heated with water and there is a solenoid that opens and closes regulating the flow of hot water water. The EOR is telling me that I need to have 36" working space in front of the access panel that houses the solenoid based on 110.26(A)(1). This class 2 power limited circuit is free-wired to the VAV and entering the VAV box with a cord connector.

Can you place a small switch labeled disconnect within sight of the equipment? and what is an EOR? Engineer Of Record?