Minimun clearances
- Thread starter alterrex
- Start date
- Status
bphgravity
Senior Member
- Location
- Florida
Re: Minimun clearances
Part III of Artcile 110 covers installations over 600V, so I'm not sure this section applies with your description of "low-voltage".
If the equipment is not likely to require examination, adjustment, servicing, or maintenance while energized, then no working space clearances are required.
Part III of Artcile 110 covers installations over 600V, so I'm not sure this section applies with your description of "low-voltage".
If the equipment is not likely to require examination, adjustment, servicing, or maintenance while energized, then no working space clearances are required.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Minimun clearances
First, what do you mean by ?low voltage?? That phrase means many things to many people.
Secondly, I do not understand your description. Are you talking about the rear access only? Are you still providing the clearances of Table 110.34(A) for the front of the switchgear? If you open the rear doors, can you see metal parts that might be energized? Are you saying that the owner will have some administrative controls in place, to ensure no attempt is ever made to perform live work from the rear of the switchgear?
You can mount the switchgear right next to a wall, if there are no renewable or adjustable parts that can only be reached from the rear. But if you have to be able to do any kind of work from the rear, you will need a minimum of 30 inches. If the work is to be done live, you will need more.
First, what do you mean by ?low voltage?? That phrase means many things to many people.
Secondly, I do not understand your description. Are you talking about the rear access only? Are you still providing the clearances of Table 110.34(A) for the front of the switchgear? If you open the rear doors, can you see metal parts that might be energized? Are you saying that the owner will have some administrative controls in place, to ensure no attempt is ever made to perform live work from the rear of the switchgear?
You can mount the switchgear right next to a wall, if there are no renewable or adjustable parts that can only be reached from the rear. But if you have to be able to do any kind of work from the rear, you will need a minimum of 30 inches. If the work is to be done live, you will need more.
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Re: Minimun clearances
It is very unlikely the equipment you are describing is ?metal-clad.? Low voltage, power switchgear (LVPS) is most likely ?dead-front, metal enclosed.? The terms are defined in the ANSI/IEEE C37.20 series and the distinction is important since ?energized? and ?live-parts? were redefined in the 2002 NEC.
Power cable terminations are made in the rear of LVPS; usually with no isolation between circuits, as you would have with true ?metal-clad? switchgear. Therefore, it is also likely that your working space requirements in the rear of this equipment will be defined directly by application of Table 110.26(A)(1) and 110.26(A)(1)(a) will not apply.
It is very unlikely the equipment you are describing is ?metal-clad.? Low voltage, power switchgear (LVPS) is most likely ?dead-front, metal enclosed.? The terms are defined in the ANSI/IEEE C37.20 series and the distinction is important since ?energized? and ?live-parts? were redefined in the 2002 NEC.
Power cable terminations are made in the rear of LVPS; usually with no isolation between circuits, as you would have with true ?metal-clad? switchgear. Therefore, it is also likely that your working space requirements in the rear of this equipment will be defined directly by application of Table 110.26(A)(1) and 110.26(A)(1)(a) will not apply.
- Status