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4160V Overhead Service to a Building

09/22/2017 3:34 PM

Greetings,

The attached photo shows a dedicated 4160 service to a 4160 chiller in a building. I feel like this installation needs to be underground and in rigid when it surfaces, but I am not finding any code references to say it's legal or not. Other than a possible clearance issue, are there any other code violation in this installation?

Thank you

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#1

Re: 4160V Overhead Service to a Building

09/22/2017 4:08 PM

What's the alleged problem?

What did the local code compliance authority say when you asked them?

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#2

Re: 4160V Overhead Service to a Building

09/22/2017 4:21 PM

How high is the bottom of the pictured drip loop?

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#3

Re: 4160V Overhead Service to a Building

09/22/2017 4:41 PM

That appears to be concrete modular construction, so it may just be within code, however, I am not the reference book of local electrical code.

Is it safe? I can't tell you that, maybe it also depends what is near that building that could knock down the conductors in a high wind. Is there ocean air, mist?

Are there abnormally tall people that could run into it?

One could ask many non-useful questions, and receive even more useless answers.

Just look up the local code, and follow the guidelines to the nearest letter.

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#4

Re: 4160V Overhead Service to a Building

09/22/2017 5:22 PM

Seems to me there should be a fence around this area and a "HIGH VOLTAGE" sign with a locked gate restricting access....

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#5
In reply to #4

Re: 4160V Overhead Service to a Building

09/22/2017 5:34 PM

What does this picture of a transformer have to do with the OP's picture?

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#6
In reply to #5

Re: 4160V Overhead Service to a Building

09/22/2017 5:43 PM

It's a picture of a warning sign on a fence, the background is irrelevant...

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#15
In reply to #6

Re: 4160V Overhead Service to a Building

09/23/2017 4:45 PM

Why is a fence, or a warning sigh, required here?

Is there a code reference requiring these things? Where's the hazard?

I refer you to: #1.

Where's the hazard?

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#16
In reply to #15

Re: 4160V Overhead Service to a Building

09/25/2017 11:01 AM

Actually SE is correct, there needs to access restriction and a warning sign for that voltage.

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#19
In reply to #16

Re: 4160V Overhead Service to a Building

09/27/2017 1:18 AM

Citation(s), please.

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#20
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Re: 4160V Overhead Service to a Building

09/27/2017 10:27 AM

Is this what you wanted?

https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10704

Over 600 volts, nominal.

1926.403(j)(1)

General. Conductors and equipment used on circuits exceeding 600 volts, nominal, shall comply with all applicable provisions of paragraphs (a) through (g) of this section and with the following provisions which supplement or modify those requirements. The provisions of paragraphs (j)(2), (j)(3), and (j)(4) of this section do not apply to equipment on the supply side of the service conductors.

..1926.403(j)(2)

1926.403(j)(2)

Enclosure for electrical installations. Electrical installations in a vault, room, closet or in an area surrounded by a wall, screen, or fence, access to which is controlled by lock and key or other equivalent means, are considered to be accessible to qualified persons only. A wall, screen, or fence less than 8 feet (2.44 m) in height is not considered adequate to prevent access unless it has other features that provide a degree of isolation equivalent to an 8-foot (2.44-m) fence. The entrances to all buildings, rooms or enclosures containing exposed live parts or exposed conductors operating at over 600 volts, nominal, shall be kept locked or shall be under the observation of a qualified person at all times.

1926.403(j)(2)(i)

Installations accessible to qualified persons only. Electrical installations having exposed live parts shall be accessible to qualified persons only and shall comply with the applicable provisions of paragraph (j)(3) of this section.

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#22
In reply to #20

Re: 4160V Overhead Service to a Building

09/27/2017 11:20 AM

No. Where are the exposed conductors? The shown ones are insulated.

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#23
In reply to #22

Re: 4160V Overhead Service to a Building

09/27/2017 12:18 PM

...and I suppose if you pointed a pistol at your own head, you would assume it unloaded?

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#24
In reply to #23

Re: 4160V Overhead Service to a Building

09/27/2017 3:20 PM

The code does not require what it does not require. Do you see signs every so many feet on every 4160-volt line running alongside the road?

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#25
In reply to #24

Re: 4160V Overhead Service to a Building

09/27/2017 3:25 PM

OK, Mr. Tornado, I am really just a molecule man, not an OSHA genius, although I thought we were focused on an industrial setting, not a roadside in the country.

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#7

Re: 4160V Overhead Service to a Building

09/22/2017 7:21 PM

What you will want to refer to is the National Electric Safety Code (NESC), C2-2012, not to be confused with NFPA-70A which most people know as the National Electric Code (NEC). The NESC is an IEEE standards document and is available for purchase through their website.

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#26
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Re: 4160V Overhead Service to a Building

09/29/2017 12:03 AM

If anyone is still following this thread, I dug into NESC C2-2012.

Per the NESC C2-2012

Part 2.

Safety Rules for the Installation and Maintenance of

Overhead Electric Supply and Communication Lines

Section 20.

Purpose, scope, and application of rules

200. Purpose

The purpose of Part 2 of this Code is the practical safeguarding of persons during the installation, operation, or maintenance of overhead supply and communication lines and their associated equipment.

201. Scope

Part 2 of this Code covers supply and communication conductors and equipment in overhead lines.

It covers the associated structural arrangements of such systems and the extension of such systems

into buildings. The rules include requirements for spacing, clearances, and strength of construction.

They do not cover installations in electric supply stations except as required by Rule 162A.

234. Clearance of wires, conductors, cables, and equipment from buildings,

bridges, rail cars, swimming pools, and other installations

C. Clearances of wires, conductors, cables, and rigid live parts from buildings, signs, billboards,

chimneys, radio and television antennas, tanks, flagpoles and flags, banners, and other installations

except bridges

3. Supply conductors attached to buildings or other installations

Where the permanent attachment of supply conductors of any class to a building or other

installation is necessary for an entrance, such conductors shall meet the following requirements

over or along the installation to which the conductors are attached:

a. Energized service drop conductors, including splices and taps, shall be insulated or covered

in accordance with the following:

(1) For 0 to 750V, Rule 230C or 230D

(2) For over 750 V, Rule 230C1

This rule does not apply to neutral conductors meeting Rule 230E1.

(SEE BELOW FOR Rule 230C1)

Section 23.

Clearances

230. General

A. Application

This section covers all clearances, including climbing spaces, involving overhead supply and

communication lines.

NOTE: The more than 70 years of historical development and specification of clearances in Rules 232, 233, and

234 were reviewed for consistency among themselves and with modern practice and were appropriately revised

in both concept and content for the 1990 Edition. See Appendix A.

1. Permanent and temporary installations

The clearances of Section 23 are required for permanent and temporary installations.

C. Supply cables

For clearance purposes, supply cables, including splices and taps, conforming to any of the

following requirements are permitted lesser clearances than open conductors of the same voltage.

Cables should be capable of withstanding tests applied in accordance with an applicable standard.

1. Cables that are supported on or cabled together with an effectively grounded bare messenger or

neutral, or with multiple concentric neutral conductors, where any associated neutral

conductor(s) meet(s) the requirements of Rule 230E1 and where the cables also meet one of the

following:

a. Cables of any voltage having an effectively grounded continuous metal sheath or shield

b. Cables designed to operate on a multi-grounded system at 22 kV or less and having

semiconducting insulation shielding in combination with suitable metallic drainage

2. Cables of any voltage, not included in Rule 230C1, covered with a continuous auxiliary semiconducting

shield in combination with suitable metallic drainage and supported on and cabled

together with an effectively grounded bare messenger.

3. Insulated, nonshielded cable operated at not over 5 kV phase to phase, or 2.9 kV phase to

ground, supported on and cabled together with an effectively grounded bare messenger or

neutral.

D. Covered conductors

Covered conductors shall be considered bare conductors for all clearance requirements except that

clearance between conductors of the same or different circuits, including grounded conductors, may

be reduced below the requirements for open conductors when the conductors are owned, operated,

or maintained by the same party and when the conductor covering provides sufficient dielectric

strength to limit the likelihood of a short circuit in case of momentary contact between conductors or

between conductors and the grounded conductor. Intermediate spacers may be used to maintain

conductor clearance and to provide support.

(The only issue I can see here is that the cable does not appear to have an effectively grounded bare messenger. The wire rope support may be grounded but I don’t believe that is the same as a messenger.)

Caveat: A licensed PE should be approving the installation drawing for this structure. That’s NOT me.

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#8

Re: 4160V Overhead Service to a Building

09/22/2017 7:29 PM

What exactly is the issue with them being that they are insulated conductors?

The clearance codes for an insulated overhead conductor are a bit different than those for open free air uninsulated ones like you would see in a typical overhead power line.

In fact one of my first jobs was working as a student co-op electrical apprentice at a local coal mine and we had huge 'Extensions cords' of sorts for 7200 VAC three phase and even 23,500 VAC three phase power for the various mine equipment that laid right on the ground where anyone on the property could walk right up and touch them.

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#9

Re: 4160V Overhead Service to a Building

09/22/2017 8:36 PM

The NEC (Article 399 if you're interested) basically just says that outdoor overhead conductor installations over 1000V must be submitted for review by an engineer to show support, installation, clearance, materials used, etc. It doesn't go into a lot of details, but it does in fact mention the NESC as a better source for information. So if the job was permitted and inspected, it must have been submitted for approval first. If not, the owner runs a risk of being shut down if someone notices. If that's the utility service entrance and the SE gear is inside of the building, then even the NEC doesn't apply, the utilities have their own rules that may or may not agree with the NEC.

That said, I've done many such installations, I see nothing wrong in that photo, but I'm not there to actually see it in person.

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#10

Re: 4160V Overhead Service to a Building

09/22/2017 9:35 PM

Thank you all for your comments. Very good input.

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#11
In reply to #10

Re: 4160V Overhead Service to a Building

09/22/2017 10:23 PM

Where in this vast world are you located?

Without us knowing your location, we're all shooting in the dark as far as codes and what's legal or not.

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#13
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Re: 4160V Overhead Service to a Building

09/22/2017 10:48 PM

4160V pretty much narrows it to North America.

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#12

Re: 4160V Overhead Service to a Building

09/22/2017 10:24 PM

I don't see a problem.

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#17
In reply to #12

Re: 4160V Overhead Service to a Building

09/25/2017 11:02 AM

You should look again. Open eyes this time, LOL.

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#14

Re: 4160V Overhead Service to a Building

09/23/2017 8:16 AM

One would think the utility had to approve the installation prior to connecting to it. They should know and understand the codes. Since it is now powered it must be done correctly.

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#18

Re: 4160V Overhead Service to a Building

09/26/2017 11:51 PM

Most often you power provider will have a manual that will lay out their requirements for installations in your area, it will give requirements for service entrances, with clearances , service loops mounting to buildings and pole mount and the building metal superstructure should provide grounding sources. This installation shows a power disconnect mounted on the pole to cut power from the transformer. One note Power Companies can overate their equipment and wire size 25% but you can't.

J.E.V

P.S. Is this a test

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#21
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Re: 4160V Overhead Service to a Building

09/27/2017 10:28 AM

And both the employer and the power provider are bound under OSHA code.

There are standards in the electric power industry, and they are there for a really good reason: When your concern for safety ceases, you become an endangered species.

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