OSHA 1926, which provides construction safety requirements, consists of Subparts A through Z. Each subpart addresses a different safety topic.
Subpart K addresses electrical safety. Compared to most other subparts, it’s significantly larger. This should not be surprising, as the practical application of electricity is complex. But another reason Subpart K is so large is that electrical accidents are among the top causes of death or injury year after year.
The good news for electricians is this OSHA standard, which is federal law, has been harmonized with the NEC. That is, OSHA relied upon the NEC for many of its requirements rather than writing them in isolation and creating conflicting safety requirements. However, Subpart K focuses on personnel safety and is much more detailed in that respect.
On the bad news side of things, there is conflict. Not between Subpart K requirements and the NEC, but between what these standards say and what people are likely to assume they say.
Here’s a question that usually gets a wrong answer: “How much clearance do you need in front of an electrical panel?” Did you answer “three feet?” That’s the normal answer, but it’s not what Subpart K and the NEC say. You’ll find the correct answer in 110.26 and in Table 110.26(A)(1) of the NEC.
If you were to look at Tables K-1 and K-2 in Subpart K, you’d see that harmonization we were just talking about. The clearance numbers agree with those the NEC provides.