Is this a violation

[FionaZuppa]

Like this...

Read the second sentence you quoted.

Cheers, Wayne

Ah, yeah.... my bad....... nevermind
haha, it's been a long day.

Why does 230.90(A) except 3 say "two to six", why two as min?

 

[bwat]

Why does 230.90(A) except 3 say "two to six", why two as min?

Because if they listed "one", that is already taken care of in 230.90(A), and wouldn't make sense as an exception. This the exception to only having one. It doesn't make sense to say you must have one and in the exception state that one is the exception to only have one.

 

[FionaZuppa]

Because if they listed "one", that is already taken care of in 230.90(A), and wouldn't make sense as an exception. This the exception to only having one. It doesn't make sense to say you must have one and in the exception state that one is the exception to only have one.

So if there's only one ocpd, the rules highlighted don't apply, but if there's more than one ocpd the rules apply to the sum of all?
EG; one ocpd that has rating = ampacity of SEC wire is ok, but I could not use rating >= ampacity of SEC wire if the calculated load was less than ampacity of wire??

230.90(A) Exception No. 3:
"Two to six circuit breakers or sets of fuses
shall be permitted as the overcurrent device to provide the
overload protection. The sum of the ratings of the circuit
breakers or fuses shall be permitted to exceed the ampacity
of the service conductors, provided the calculated load
does not exceed the ampacity of the service conductors."

It's again NEC words that need fixing. "two to six" followed by the singular word "device"?? It should read "Two to six circuit breakers or sets of fuses shall be permitted as the overcurrent devices ...."

 

[david luchini]

So if there's only one ocpd, the rules highlighted don't apply, but if there's more than one ocpd the rules apply to the sum of all?

That's correct. The highlighted rule doesn't apply to a single ocpd. There is no "sum of the ratings" for a single ocpd.

EG; one ocpd that has rating = ampacity of SEC wire is ok, but I could not use rating >= ampacity of SEC wire if the calculated load was less than ampacity of wire??

Not quite. The rating of the single ocpd can be greater than the ampacity of service entrance conductor per ex. 2.

 

[kwired]

There's something weird about that drawing. They call the top breaker the main, but both breakers are in parallel.

I believe if you install a single main it needs to go in that position, probably where there is provision for an attachment device that would be required for a back fed breaker. But the instructions that were posted do say there can be up to six disconnecting means for this unit. Some clearly state they are only suitable for use as service equipment when there is a single main. These instructions do include the term "lighting and appliance panelboard" that is no longer in recent codes, so it is likely been some time since it was manufactured as well.

 

[nickelec]

To clarify again on 2008 code we all agree it's compliant on accordance with 230.91

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[jim dungar]

It's again NEC words that need fixing. "two to six" followed by the singular word "device"??

No. The NEC has it correct.

Section 230.90, clearly, addresses a single device.
The exception, in question, says it is permissible to consider multiple devices as if they were a single device, when applying the language used in 230.90.

 

[kwired]

What do you gentlemen think of this email?


Good afternoon this is the second time I've had an inspector fail me for this installation and i'm looking for some clarification. The inspector stated I am violating 240.21. Clearly this is not a tap as per the NEC definitions is A conductor, other than a service conductor, that has. overcurrent protection ahead of its point of supply that exceeds. the value permitted for similar conductors that are protected as. described elsewhere in 240.4

my argument is article 230. 90 (A)(1) Exp 3, specifically states Two to six circuit breakers or sets of fuses shall be permitted as the overcurrent device to provide the overload protection. The sum of the ratings of the circuit breakers or fuses shall be permitted to exceed the ampacity of the service conductors, provided the calculated load does not exceed the ampacity of the service conductors.


the above exception depicts and clarifies the installation I have below please see attached photos. The conductors in the picture that land directly on the bus in the service switch that is rated for use as service equipment are directly coming from the utility size number 2 copper conductors




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I agree with your position on this. What is in question here is service conductors, there is no "tap rules" for service conductors. The "tap" definition is in 240.2, and 240.21 only uses this term in 240.21 (A) and (B) for branch ciruits and feeders and in (F) for motor circuit taps. Is not mentioned at all in (D) for service conductors


Most all of what is in 2008 is very similar to what is in 2017, mostly minor changes and not much that changes the main concepts of what is generally required from that section.

 

[kwired]

To clarify again on 2008 code we all agree it's compliant on accordance with 230.91

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yes

 

[texie]

As pointed out by others, the inspector is wrong. He is not even in the right ballpark. Until the 2020 edition this is a compliant install. But I gotta ask... while neither one needs it, why did you use a bonding bushing for the panel on the left but not on the conduit for the other feeder?

 

[nickelec]

One of my guys did it by mistake

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[oldsparky52]

How many mounting screws are in that can?

 

[FionaZuppa]

Not quite. The rating of the single ocpd can be greater than the ampacity of service entrance conductor per ex. 2.

Per your notes, where 230.90(A)Ex3 applies only to 2-6, 230.90(A)Ex2 applies to 1, the below is compliant?

one set 3wire 240vCT SEC » service box » 6 ocpd's

Ampacity of SEC's = 185A
ocpd 1 = rated 200A
ocpd 2 = rated 40A
ocpd 3 = rated 40A
ocpd 4 = rated 40A
ocpd 5 = rated 40A
ocpd 6 = rated 40A

Calc load for ocpd 1 = 160A
Calc load for ocpd 2 = 30A
Calc load for ocpd 3 = 30A
Calc load for ocpd 4 = 30A
Calc load for ocpd 5 = 30A
Calc load for ocpd 6 = 30A

Calc Load Sum of 1 = 160
Rating Sum of 1 = 200
Calc Load Sum of 2-6 = 150
Rating Sum of 2-6 = 200

I agree with your position on this. What is in question here is service conductors, there is no "tap rules" for service conductors. The "tap" definition is in 240.2, and 240.21 only uses this term in 240.21 (A) and (B) for branch ciruits and feeders and in (F) for motor circuit taps. Is not mentioned at all in (D) for service conductors


Most all of what is in 2008 is very similar to what is in 2017, mostly minor changes and not much that changes the main concepts of what is generally required from that section.

This is interesting....... doesn't NEC address SEC taps?

230.33 Spliced Conductors. Service-lateral conductors shall be
permitted to be spliced or tapped in accordance with
110.14, 300.5(E), 300.13, and 300.15.

230.46 Spliced Conductors. Service-entrance conductors
shall be permitted to be spliced or tapped in accordance
with 110.14, 300.5(E), 300.13, and 300.15.

 

[david luchini]

Per your notes, where 230.90(A)Ex3 applies only to 2-6, 230.90(A)Ex2 applies to 1, the below is compliant?

No. You have 6 ocpds, but you dont comply with the requirements of the exception.

 

[FionaZuppa]

No. You have 6 ocpds, but you dont comply with the requirements of the exception.

Which part of it does not comply with the exceptions?

 

[kwired]

Per your notes, where 230.90(A)Ex3 applies only to 2-6, 230.90(A)Ex2 applies to 1, the below is compliant?

one set 3wire 240vCT SEC » service box » 6 ocpd's

Ampacity of SEC's = 185A
ocpd 1 = rated 200A
ocpd 2 = rated 40A
ocpd 3 = rated 40A
ocpd 4 = rated 40A
ocpd 5 = rated 40A
ocpd 6 = rated 40A

Calc load for ocpd 1 = 160A
Calc load for ocpd 2 = 30A
Calc load for ocpd 3 = 30A
Calc load for ocpd 4 = 30A
Calc load for ocpd 5 = 30A
Calc load for ocpd 6 = 30A

Calc Load Sum of 1 = 160
Rating Sum of 1 = 200
Calc Load Sum of 2-6 = 150
Rating Sum of 2-6 = 200

Unless there is some demand factor that can be applied to the common supply conductor that otherwise can't apply to individual feeders that will bring the final calculation down enough, you have more load than the ampacity of the common supply conductor.

I had an install once that had main lug I line panel (800 amp bus) as the service equipment, only had 4 breakers installed, 2- 400's 2- 125's. Don't recall exact ampacity of supply conductors but remember it was between 700 and 800.

Don't recall exact load calculation anymore but think it was only around 500 amps, and would bet majority of time never exceeds 350 amps.

Now once 2020 NEC comes into play that install wouldn't be allowed to be all in one panel anymore, but still would be able to put say a aux gutter or splice box and still install same values of OCPD's in separate enclosures or in separate vertical sections of a switchboard.

This is interesting....... doesn't NEC address SEC taps?

For overcurrent protection is says very little in 240.21 and basically has no rule(s) that is similar to those for feeders or transformer secondary conductors. They are still service conductors with potentially pretty unlimited protection from whatever they are supplied by and therefore still have limitations on how much conductor can even enter a building - though that rule is kind of vague and is interpreted differently in nearly every jurisdiction out there.

 

[david luchini]

Which part of it does not comply with the exceptions?

You have 310A of load and secondary conductors with an ampacity of 185A.

 

[jim dungar]

... 230.90(A)Ex3 applies only to 2-6, 230.90(A)Ex2 applies to 1, the below is compliant?

You are totaly misreading the NEC.

You can either have 1 service protective device or you can have 2, or 3, or 4, or 5, or 6 protective devices. Based on the exception all of these 6 possibilities are treated the same way, as if you only have 1 service.

In your example you are trying to say the NEC treats the first protective device differently than it treats the remaining devices # 2 through #6. That is wrong.

 

[FionaZuppa]

You are totaly misreading the NEC.

You can either have 1 service protective device or you can have 2, or 3, or 4, or 5, or 6 protective devices. Based on the exception all of these 6 possibilities are treated the same way, as if you only have 1 service.

In your example you are trying to say the NEC treats the first protective device differently than it treats the remaining devices # 2 through #6. That is wrong.

Isn't that what post #64 says, the Ex rules only apply to ocpd's 2/3/4/5/6, and not to just one ocpd? Why would the rules of Ex3 not apply to a single ocpd?
I assumed the "sum" rules and "calc load" rules applied to ALL devices used as ocpd's that serve as the disco/ocpd for SEC's.

 

[FionaZuppa]

Unless there is some demand factor that can be applied to the common supply conductor that otherwise can't apply to individual feeders that will bring the final calculation down enough, you have more load than the ampacity of the common supply conductor.

I had an install once that had main lug I line panel (800 amp bus) as the service equipment, only had 4 breakers installed, 2- 400's 2- 125's. Don't recall exact ampacity of supply conductors but remember it was between 700 and 800.

I was using post #64 to craft the example.
Post #64 did not make sense to me.