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 Post subject: Zero Voltage Verification
PostPosted: Thu May 09, 2013 6:17 pm 

Joined: Fri Jan 06, 2012 1:26 pm
Posts: 3
When doing group lockout does each person installing lockout device have to personally verify zero voltage, or can one person verify while others watch?

Where can I find the answer

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PostPosted: Mon May 13, 2013 8:23 am 

Joined: Wed May 06, 2009 12:12 pm
Posts: 26
Location: Tennessee
We require one lock per person but we only require one "Verification". We encourage all electricians to test before they touch.

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PostPosted: Mon May 13, 2013 8:39 am 

Joined: Thu Jan 17, 2013 2:27 pm
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Best LOTO resource I have found, and it is free. It is the document OSHA uses to train their inspectors. You will have to down load the PDF. Go to page 4-2 to start the information on group LOTO. Better material on 4-7.

If you are not using a system with a primary authorized employee, then everyone would need to either personally verifiy or witness the verification process.

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PostPosted: Wed May 15, 2013 4:58 am 
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Joined: Fri May 01, 2009 9:10 am
Posts: 73
App NC... Thanks for the link!

The relevant codes are 29CFR 1910.333, 1910.147, and you can also reference NFPA 70E Article 120.2(D).

There is a little bit of "Catch-22" when reading 1910.147(a)(1)(ii)(C) where is states that 1910.147 does not apply to work on or near energized electrical equipment and then refers you to Subpart S (1910.300 - 399). When reading 1910.333(b)(2) Note 2, it states that you can use 1910.147 paragraphs c through f to fulfill the requirements. So, we can combine those 2 codes to develop a LOTO procedure that MUST be documented.

1910.147(f)(3) covers group lockout but doesn't cover electrical. 1910.333 covers electrical but not group LOTO. It is going to be the employer's responsibility to develop, document, and train the employees with regard to LOTO on electrical equipment. IMHO, it is acceptable, and widely practiced, to assign primary responsibility to a single QUALIFIED employee (as indicated in 1910.147) provided he/she uses the work practices defined in 1910.333. Here is a brief list of the minimum LOTO procedures that the employee assigned as the primary should follow:

1 - Identify all energy sources
2 - Notify affected personnel of impending LOTO
3 - Shut down equipment in an orderly manner if possible
4 - Open disconnecting devices
5 - If possible verify all blades are fully open
6 - Apply LOTO
7 - Verify with an adequately rated detector that it is deenergized. Check detector before & after if >600V nominal.
8 - Ground the phase conductors if deemed necessary.

Another documented procedure would allow any qualified person (assigned to the job) to verify the absence of voltage after LOTO was performed. Some people I trust, but there are many that I do not trust so I want to have that option available. The equipment and circumstances would also have an impact on whether I double check.

The Group LOTO question can also be rolled over to cover equipment that is down across multiple shifts/crafts. Do we allow the oncoming shift to check for the absence of voltage or just dive right into the repairs?

Disclaimer: this post is for general information only and should not be used as a LOTO procedure. It is the reader's responsibility to know and understand the codified requirements and act in a just and prudent manner.

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PostPosted: Thu May 16, 2013 6:10 pm 
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Location: North Carolina
1910.333 makes it clear that 1910.147 can only be substituted when it fully complies with the requirements of 1910.333. And as stated, 1910.333 does not support group lockout at all. So you can use the LOTO procedure in 1910.333 as the "lockout" and then others can lock out on it but not vice versa. Specifically of all the requirements in 1910.333, unqualified personnel can shut the equipment down and apply locks. ALL other steps, including hazard recognition, testing to verify that a restart is not possible, and all the obvious "electrical" steps must be performed by a qualified person.

Also, 1910.333 doesn't specifically disallow group lockout at all. It has a set of specific requirements but does not dictate it to the same level of detail as 1910.147. It is also beneficial to look at 1910.269. There is a bit of a trick here because 1910.269 contains two complete and distinct LOTO procedures, and more than one method. The first section applies to generating stations and is not dissimilar to 1910.147 and 1910.333. The second one applies to transmission and distribution lines and is a bit more interesting. Not only does it allow for group lockout but it also allows for a sort of "virtual lockout" where a remote operator "locks out" the equipment for the line crews without the crews actually directly applying locks. I understand the need for this but I don't like it one bit and chose not to implement this procedure for our distribution crews.

For completeness, also look over at 1926. This also has an electrical LOTO. Interestingly it mandates tagging but not locks, unlike the 1910 series that always requires a lock and sometimes a tag. It is definitely required in many cases in industrial plants based on the interpretations of construction vs. maintenance, BUT fortunately 1910.147 and 1910.333 go so far beyond it (except that they don't mandate tags) that most of the time it is possible to ignore 1926. Also look at Subchapter O under 1910. This is for operational/service "lockouts" which really only requires a well documented procedure and a risk analysis. This is the basis for using various safety rated devices on the market to do things during production that would otherwise full lockout for maintenance purposes.

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