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#150451 - 04/09/05 07:35 AM GFCI protection at construction sites
safetygem Offline
Member

Registered: 01/30/02
Posts: 114
Loc: Ohio, USA
OSHA answered two question in a recent letter of interpretation to an employer. I thought the "questions and answers" would be of interest to the group.

Here is Question #1. Feel free to comment or ask your own related question(s).

Glenn

Question (1): Does Part 1926 Subpart K require that all 120-volt, single-phase outlets have ground fault circuit interrupter (GFCI) protection? Also, does Subpart K say that outlets with voltages above 120 volts do not have to be protected from ground faults?

Answer: The answer to both questions is no. Section 1926.404(b)(1)(i) provides:

(b) Branch circuits -- (1) Ground-fault protection
(i) General. The employer shall use either ground fault circuit interrupters as specified in paragraph (b)(1)(ii) of this section or an assured equipment grounding conductor program ["AEGCP"] as specified in paragraph (b)(1)(iii) of this section to protect employees on construction sites. [Emphasis added.] These requirements are in addition to any other requirements for equipment conductors.

Therefore, under paragraph 1926.404(b)(1)(i), the employer is required to provide ground fault protection -- either by the use of
ground fault circuit interrupters (GFCIs) or by the use of an assured equipment grounding conductor program. Note that there is no voltage limit to this requirement.

The first option for meeting the requirement that there be ground fault protection is by the use of GFCIs. The requirements for that option are spelled out in paragraph 1926.404(b)(1)(ii):

(ii) Ground-fault circuit interrupters. All 120-volt, single-phase, 15- and 20- ampere receptacle outlets on construction sites, which are not part of the permanent wiring of the building or structure and which are in use by employees, shall have approved ground-fault circuit interrupters for personnel protection.
* * *

The other option for meeting the requirement that there be ground fault protection is by the use of an assured equipment grounding conductor program. The requirements for that option are spelled out in paragraph 1926.404(b)(1)(iii). While there are several applicable provisions of paragraph 1926.404(b)(1)(iii), we note two in particular:

(iii) Assured equipment grounding conductor program. The employer shall establish and implement an assured equipment grounding conductor program on construction sites covering all cord sets, receptacles which are not a part of the building or structure, and equipment connected by cord and plug which are available for use or used by employees.
* * *
(B) The employer shall designate one or more competent persons (as defined in §1926.32(f)) to implement the program. [Emphasis added.]
* * *
(F) The employer shall not make available or permit the use by employees of any equipment which has not met the requirements of this paragraph (b)(1)(iii) of this section. [Emphasis added.]

In your letter you focus on the part of paragraph 1926.404(b)(1)(ii) -- the GFCI option -- that refers to 120-volt outlets being protected by GFCIs. That part of paragraph 1926.404(b)(1)(ii) means that the GFCI option, as written, was available only for 120-volt, single-phase, 15- and 20-ampere receptacle outlets. Because there is no voltage limit to the requirement in 1926.404(b)(1)(i) to provide ground fault protection by one of the two listed options (GFCI or assured grounding program), as originally written the standard in effect required that outlets over 120 V had to be protected by an assured grounding program.

However, as we explained in our May 15, 2002, Mercuris letter, the 120-V limitation for use of the GFCI option was put in the standard only because GFCIs for higher voltages were generally unavailable at the time the standard was promulgated. Since then GFCIs have become available for higher voltages. So, as we stated in Mercuris, use of a GFCI to protect a circuit with a voltage higher than 120 volts would be acceptable to meet the paragraph 1926.404(b)(1)(i) ground fault protection requirement. It would be considered only a de minimis* violation as long as the GFCI was designed to protect a circuit of that voltage.

In sum, under §1926.404(b)(1)(i), employers must provide ground fault protection. This requirement is not limited to 120-V outlets -- it applies to outlets with higher voltages as well. Employers have two options for meeting this requirement -- by using GFCIs designed for the particular voltage or by implementing an assured equipment grounding conductor program.

* Under OSHA's de minimis policy, de minimis violations are those which have no direct or immediate relationship to safety or health. Consequently, no citation is issued.

Edited to add definition of de minimis.

[This message has been edited by safetygem (edited 04-09-2005).]

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#150452 - 04/16/05 04:48 AM Re: GFCI protection at construction sites
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Glenn,
Interesting topic.
I just have one question.
 Quote:
or an assured equipment grounding conductor program

What exactly is this?, I'm guessing it's like our old Monitored Earth system over here in NZ, that is very rarely used now.
It was used for all-metal power tools and used a transformer and a cut-out relay.
Is this something similar?.

Mike.


[This message has been edited by Trumpy (edited 04-16-2005).]
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#150453 - 04/16/05 01:06 PM Re: GFCI protection at construction sites
renosteinke Offline
Cat Servant
Member

Registered: 01/22/05
Posts: 5305
Loc: Blue Collar Country
"assured grounding" means little more than management frequently inspecting tools and cords to ensure that the ground prongs haven't been cut off. Bonding wires to the structure, grounding electrode, etc., are also supposed to be inspected and tested regularly.

Properly executed, this can work. It can also apply to all "flavors" of electricity, not just the single-phase 120/240 low current parts (that GFI's are limited to). Lest we also forget, construction sites are full of operations (such as welding) that USE current 'leakage' to work.

One thing that is becoming rarer, though, are power tools with three-prong plugs; almost everything comes "double insulated" these days. Absent any sort of ground, there is still a place for GFI's.

OSHA, like any govt agency, will try to do two things: write a 'one size fits all' rule, and exclude any place for thoughtful judgement to be exercised.

The electrical contractor is the expert here; it is his judgement that counts, and his interpretation of the rules- not the general contractors' opinion. The GC has three responsibilities: schedule the job, pick up the trash, and pay the subs. Let him fulfill those obligations first!

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#150454 - 04/16/05 05:10 PM Re: GFCI protection at construction sites
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Thanks for explaining that one for me John!.



[This message has been edited by Trumpy (edited 04-16-2005).]
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Let's face it, these days if you're not young, you're old - Red Green grin

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#150455 - 04/22/05 01:58 AM Re: GFCI protection at construction sites
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
John,
That's a rather interesting point you bring up about welding machines introducing current into the installation.
Can this cause GFCI's to trip?.
I was under the impression that welders used a simple return circuit to return all of the current back to the welder output via the Earth Clamp.
Mind you, once in the Fire Station here, we had a weldor working here and he cooked our Alarm panel, through the current getting into the building Earthing system.
So what gives?.

Mike.




[This message has been edited by Trumpy (edited 04-22-2005).]
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Let's face it, these days if you're not young, you're old - Red Green grin

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#150456 - 04/23/05 10:17 AM Re: GFCI protection at construction sites
renosteinke Offline
Cat Servant
Member

Registered: 01/22/05
Posts: 5305
Loc: Blue Collar Country
Sometimes we forget the simple stuff...electricity takes ALL paths, in relation to their (lack of) resistance. So it is possible for 1 90 amp welding arc to have 85 amps return via the ground clamp, and 5 amps find some other path.
Indeed, one of the things a welder has to watch out for is the current inadvertantly flowing through bearings and such, causing damage.

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#150457 - 05/01/05 03:49 AM Re: GFCI protection at construction sites
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Yes John that is a simple but forgotten fact.
Thanks for bringing that up.
Like any other current, it conforms to Ohms Law with respect to Current division.
Or is it more Kirchoffs Law?.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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#150458 - 05/01/05 01:21 PM Re: GFCI protection at construction sites
iwire Offline
Moderator

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
 Quote:
Lest we also forget, construction sites are full of operations (such as welding) that USE current 'leakage' to work.


Wouldn't a welder be essentially a separately derived system?

As such there would be no other path for electricity to take.
_________________________
Bob Badger
Construction & Maintenance Electrician
Massachusetts

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#150459 - 05/01/05 09:31 PM Re: GFCI protection at construction sites
renosteinke Offline
Cat Servant
Member

Registered: 01/22/05
Posts: 5305
Loc: Blue Collar Country
IWire, I don't know about "separately derived"...but the damage caused by unanticipated arcs when the welding current finds unexpected paths- such as through bearings- is very real. I've also managed to get zapped a few times when welding.
Welding is one thing that mystifies me. I've actually seen someone arc-weld a patch on a pipe that was gushing a major amount of water, under some pressure, at the time.

In all honesty, I've never tried a welder on a GFI circuit, so I really can't say for sure that there's a problem there....but it seems likely :-)

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