NEC 110.26 requires working clearance in front of equipment likely to require calibration, testing, or adjustment while energized. This means a 30 by 36 inch space (or larger) in front of panels, access panels on HVAC equipment and fused disconnects. Does this requirement extend to non-fused disconnects? I am thinking specifically of the service disconnects often found installed 12-18 inches behind AC compressors in the side or back yard of dwelling units.
When there is a problem with a piece of equipment the first thing many troubleshooters will do is check for voltage at the load side of the disconnect serving the equipment. This requires 110.26 work space. Even OSHA permits troubleshooting hot. Don
Re: working clearance 110.26#89727 10/17/0403:02 AM10/17/0403:02 AM
As the installing electrician, I would like to keep the area in front of my disconnecting switch relatively clear. As the inspector, I can, and do, cite the electrician for not leaving working space in front of the disconnect. As the trouble call electrician I have wished the installing electrician had left enough room in front of the disconnect for me to be able to test for voltages without having to perform contortions. I have heard of this call being made by other inspectors where it was OK to crowd the disconnect behind equipment if there was another disconnect before the "workman's switch" that could be locked in the off position. The explanation given was the workman's switch wasn't even required, so it needn't have a working clearance. As an electrician, I have also had to install disconnects behind equipment, knowing there wasn't enough "working clearance" room because there simply wasn't room to install it anywhere else. How do you guys handle that situation? Does it make a difference if the switch is a ball-bat type with a screwed-on faceplate or if the switch is a HD safety switch with a hinged cover easily opened for voltage testing? This is how I have differentiated between the two situations in the past: Is it likely to be used for voltage testing? If yes, then you need a working clearance. Who agrees? Who doesn't?
Re: working clearance 110.26#89729 10/17/0410:38 AM10/17/0410:38 AM
This working space issue is always going to be a judgement call. Who is to say that the disconnect behind an AC is more likely to need service than the receptacle under the sink for the disposal. As soon as you make a decision, you will be wrong on your next service call. Anyone who has crawled on his belly in a 140 degreee 3:12 attic full of blown in insulation, looking for a J box, will question the "accessible" rule too. :-)
Re: working clearance 110.26#89731 10/17/0412:04 PM10/17/0412:04 PM
I'm with Don as well. I don't think fuses enter into it.
I also see everyone elses point as well, which is why I have been working on a proposal (for months now) to change the text of 110.26 to include a list format of the equipment it applies to, but that brings up its own issues as well. It really is a difficult subject.