Fused EGC

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Re: Fused EGC

I think 240.22 says it all:

"240.22 Grounded Conductor:
No overcurrent device shall be connected in series with any conductor that is intentionally grounded, unless one of the two following ...."

(I left out the unless because I don't think they apply, but please look up the paragraph and judge for yourselves).

Correct me if I'm wrong, but I think "intentionally grounded" would include both neutrals and EGC's and GEC's and other flavors.
Steve ;)

[ October 14, 2005, 12:57 PM: Message edited by: steve66 ]
 
Re: Fused EGC

I think 240.22 is a bit of a stretch. Only because when we start trying to use terms out of context the waters get too muddy for my liking. Yes, the grounding conductor is "intentionally grounded", but it's not the same as the grounded conductor . 240.22 specifically says "grounded conductor," not bonding, GEC, EGC, etc. It could be revised though. :)

I am not saying that I think this installation is legal in any way, just that it appears that the code does't directly address this issue. I think 250.4(A)(5) is as close as we are going to get.

[ October 14, 2005, 02:24 PM: Message edited by: peter d ]
 
Re: Fused EGC

To use 240.22 we would have to apply the whole section which states:

240.22 Grounded Conductor.
No overcurrent device shall be connected in series with any conductor that is intentionally grounded, unless one of the following two conditions is met:
(1) The overcurrent device opens all conductors of the circuit, including the grounded conductor, and is designed so that no pole can operate independently.
(2) Where required by 430.36 or 430.37 for motor overload protection. [/QOUTE]

This disconnect opens all of the conductors as is designed so that no one conductor can be opened independently of the others. Therefore 240.22 would not apply unless this is the grounded (neutral) conductor. If it is the grounded (neutral) conductor then only 250.142 (B) is violated.

We also have to identify which conductor is in question. 240.22 is addressing the grounded (neutral) and not the equipment grounding conductor.

We sometimes forget that it is the grounded (neutral) conductor that is intentionally grounded (connected to earth) and not the equipment grounding conductor.
The equipment grounding conductor is an intentionally constructed path designed to carry current under ground-fault conditions on a wiring system to the electrical supply source and not to the earth.
:)
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Re: Fused EGC

Originally posted by steve66:
I think 240.22 says it all:
.........Correct me if I'm wrong, but I think "intentionally grounded" would include both neutrals and EGC's and GEC's and other flavors.
Steve ;)
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Steve I tried to make that work but go to article 100 and you find that the definition of an EGC does not include intentionally grounded.

The problem is an ungrounded system still has an EGC so we can not say an EGC is intentionally grounded conductor.

Grounding Conductor, Equipment. The conductor used to connect the non?current-carrying metal parts of equipment, raceways, and other enclosures to the system grounded conductor, the grounding electrode conductor, or both, at the service equipment or at the source of a separately derived system.
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Grounded Conductor. A system or circuit conductor that is intentionally grounded.
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So far IMO the most relevant section is 250.4(A)(5) as Pete brought up @ 10-12-2005 17:51.
 
Re: Fused EGC

I still feel that 240.22 was intended to apply to EGC's and bonding wires. I think it is just poorly worded. If we look at the definition of "Grounded" you get:

"Connected to earth or to some conducting body that serves in place of the earth."

In the case of an ungrounded system, I would say the conduit, EGC's, bonding, and metal cases of equipment substitute for the earth.

I would also say that in this context, maybe a "Grounded Conductor" is meant to be any conductor that is "grounded" per the definition of "grounded". This could be interperted differently than the definiton of "grounded conductor".

Just my humble opinion.

Jwelectric: The disconnect may open all phases, but per the definition one fuse would also have to open all phases, which it doesn't.

Steve
 
Re: Fused EGC

Steve, we will just have to agree to disagree. :) As I said earlier, when we start bunching grounded, grounding etc it muddies the waters too much. I think the code is clear on this particular issue.
 
Re: Fused EGC

Originally posted by steve66:
I still feel that 240.22 was intended to apply to EGC's and bonding wires. I think it is just poorly worded. If we look at the definition of "Grounded" you get:

"Connected to earth or to some conducting body that serves in place of the earth."

In the case of an ungrounded system, I would say the conduit, EGC's, bonding, and metal cases of equipment substitute for the earth.
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Note the difference in the installations outlined below. The equipment grounding conductor is still used as a path to clear the fault and serves a different function than a grounded (neutral) conductor.

240.4 (B) Ungrounded Systems.
(1) Grounding Electrical Equipment. Non?current-carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected to earth in a manner that will limit the voltage imposed by lightning or unintentional contact with higher-voltage lines and limit the voltage to ground on these materials.

(4) Path for Fault Current. Electrical equipment, wiring, and other electrically conductive material likely to become energized shall be installed in a manner that creates a permanent, low-impedance circuit from any point on the wiring system to the electrical supply source to facilitate the operation of overcurrent devices should a second fault occur on the wiring system. The earth shall not be considered as an effective fault-current path.
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Originally posted by steve66:
I would also say that in this context, maybe a "Grounded Conductor" is meant to be any conductor that is "grounded" per the definition of "grounded". This could be interperted differently than the definiton of "grounded conductor".
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I agree with you on this statement due to the fact that the grounded conductor (neutral conductor) is exactly what is connected to ground (earth).

Originally posted by steve66:
Jwelectric: The disconnect may open all phases, but per the definition one fuse would also have to open all phases, which it doesn't.
Steve
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Please take a few minutes to explain to me how you would connect more than one phase (ungrounded) conductor to one fuse. :)
 
Re: Fused EGC

Originally posted by jwelectric:
Please take a few minutes to explain to me how you would connect more than one phase (ungrounded) conductor to one fuse. :)
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You can not use fuses in a standard disconnect when applying 240.22. :)
 
Re: Fused EGC

Bob,
Here is the code references I would use as an inspector.

First:
250.124 (B) (B) Switches. No automatic cutout or switch shall be placed in the equipment grounding conductor of a premises wiring system unless the opening of the cutout or switch disconnects all sources of energy.

The "automatic cutout" is the fuse. If this were a breaker, it would be OK by this code reference.

Then there is this:
250.126 Identification of Wiring Device Terminals.
The terminal for the connection of the equipment grounding conductor shall be identified by one of the following:
(1) A green, not readily removable terminal screw with a hexagonal head.
(2) A green, hexagonal, not readily removable terminal nut.
(3) A green pressure wire connector. If the terminal for the grounding conductor is not visible, the conductor entrance hole shall be marked with the word green or ground, the letters G or GR, a grounding symbol, or otherwise identified by a distinctive green color. If the terminal for the equipment grounding conductor is readily removable, the area adjacent to the terminal shall be similarly marked.

Device. A unit of an electrical system that is intended to carry but not utilize electric energy.

Not to mention this reference:
250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes.
 
Re: Fused EGC

a fuse is not a type of equipment grounding conductor, look at 250.118 (1)
 
Re: Fused EGC

Posted by jwelectric:

Please take a few minutes to explain to me how you would connect more than one phase (ungrounded) conductor to one fuse.
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You can't (unless you want to try pierre's method). So my point was that you can't have a fuse in the grounded conductor because it can't open all phases. :)

If I am the only one who thinks 240.22 applies to all the flavors of ground wires, then I will concede. I think we all still agree the ""permanent, low impedance circuit." and "capable of carrying a fault current" quotes still rules out a fuse in the ground conductor.

Steve
 
Re: Fused EGC

:)

If I am the only one who thinks 240.22 applies to all the flavors of ground wires, then I will concede. I think we all still agree the ""permanent, low impedance circuit." and "capable of carrying a fault current" quotes still rules out a fuse in the ground conductor.

Steve [/QB]
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I definatly agree with you on the last part of your statement. But it seems clear that 240.22 is refering to "grounded" and not "grounding" conductors. :D

____________________
Wes Gerrans
Instructor
Northwest Kansas Technical College
Goodland Kansas
 
Re: Fused EGC

I am still wondering why they used the phrase "conductors that are intentionally grounded" instead of just saying "grounded conductors".

Steve
 
Re: Fused EGC

Originally posted by websparky:
[Then there is this:
250.126 Identification of Wiring Device Terminals.
The terminal for the connection of the equipment grounding conductor shall be identified by one of the following:
(1) A green, not readily removable terminal screw with a hexagonal head.
(2) A green, hexagonal, not readily removable terminal nut.
(3) A green pressure wire connector. If the terminal for the grounding conductor is not visible, the conductor entrance hole shall be marked with the word green or ground, the letters G or GR, a grounding symbol, or otherwise identified by a distinctive green color. If the terminal for the equipment grounding conductor is readily removable, the area adjacent to the terminal shall be similarly marked.

Device. A unit of an electrical system that is intended to carry but not utilize electric energy.
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I don't think that code section is valid in this case since most disconnects require a separately sold ground bar kit. The ground bars never have green terminals that meet this code rule. Even the basic A/C disconnects that include the grounding terminals aren't green.
 
Re: Fused EGC

Bob,

240.22(2) refers you to 430.36, I have not seen this referanced in the thread.

It says with 3 wire 3ph with 1 grounded conductor,where fuses are used as the overload protection,then the grounded phase shall also be fused?

Without knowing the voltage for sure,this could be what you have shown.

But I doubt it.
 
Re: Fused EGC

Bob,

200.10 Identification of terminals.

Will this work for you.

----shall have terminals properly marked for identification----
 
Re: Fused EGC

Iwire...as for landing a EGC on the fused block of that disconnect, 250.8 would be one code section selection that make that disconnect non- compliant with the NEC...

shortcircuit2
 
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