Sizing tap conductors between feeder and breaker where tap terminates

[quantboy5]

I just wanted to make sure I was interpreting the code correctly.

I have a 240VAC line, that is protected by a 100Amp breaker. This line is a #2 CU conductor that was run thru conduit (115A per 310.15(b)(16)).
I wanted to tap this line in the middle, and bring the tap conductor to a 40A breaker, that feeds the new equipment loads.
The tap wire from the point where it would be tapped, to the 40A breaker is about 8 feet away.

Can I use 240.21(1) that applies to "Taps not over 3m Long"?

If so, I was planning on using a #8 cu. conductor for the wire from the point of tapping to the 40A breaker (50A per 310.15(b)(16).).

The tapped wire is planned to be run in square, plastic conduit, in a personnel restricted area.

 

[tkb]

I just wanted to make sure I was interpreting the code correctly.

I have a 240VAC line, that is protected by a 100Amp breaker. This line is a #2 CU conductor that was run thru conduit (115A per 310.15(b)(16)).
I wanted to tap this line in the middle, and bring the tap conductor to a 40A breaker, that feeds the new equipment loads.
The tap wire from the point where it would be tapped, to the 40A breaker is about 8 feet away.

Can I use 240.21(1) that applies to "Taps not over 3m Long"?

If so, I was planning on using a #8 cu. conductor for the wire from the point of tapping to the 40A breaker (50A per 310.15(b)(16).).

The tapped wire is planned to be run in square, plastic conduit, in a personnel restricted area.

I don’t remember a square plastic conduit listed in chapter 3.

 

[raider1]

I just wanted to make sure I was interpreting the code correctly.

I have a 240VAC line, that is protected by a 100Amp breaker. This line is a #2 CU conductor that was run thru conduit (115A per 310.15(b)(16)).
I wanted to tap this line in the middle, and bring the tap conductor to a 40A breaker, that feeds the new equipment loads.
The tap wire from the point where it would be tapped, to the 40A breaker is about 8 feet away.

Can I use 240.21(1) that applies to "Taps not over 3m Long"?

Yes you can use 240.21(B)(1) if the total length of the tap conductors does not exceed 10'

If so, I was planning on using a #8 cu. conductor for the wire from the point of tapping to the 40A breaker (50A per 310.15(b)(16).).

Yes a #8 copper conductor would be suitable for this installation.

The tapped wire is planned to be run in square, plastic conduit, in a personnel restricted area.

This would be fine provided that the square plastic conduit is Listed as a "Surface Nonmetallic Raceway" and installed per Article 388.

Chris

 

[texie]

I just wanted to make sure I was interpreting the code correctly.

I have a 240VAC line, that is protected by a 100Amp breaker. This line is a #2 CU conductor that was run thru conduit (115A per 310.15(b)(16)).
I wanted to tap this line in the middle, and bring the tap conductor to a 40A breaker, that feeds the new equipment loads.
The tap wire from the point where it would be tapped, to the 40A breaker is about 8 feet away.

Can I use 240.21(1) that applies to "Taps not over 3m Long"?

If so, I was planning on using a #8 cu. conductor for the wire from the point of tapping to the 40A breaker (50A per 310.15(b)(16).).

The tapped wire is planned to be run in square, plastic conduit, in a personnel restricted area.

You are trying to tap a tap. That is not compliant.
Also, are you referring to something like Panduit finger type? This would not be a Chapter 3 wiring method.

 

[raider1]

I don’t remember a square plastic conduit listed in chapter 3.

Article 388 Surface Nonmetallic Raceways covers square 2 part raceway systems for surface mounting.

Chris

 

[quantboy5]

Thanks for the replies....
It is NOT tapping a tap... it's tapped right off the main feeder, coming from the 100A breaker protecting it.
Square raceway is not "Panduit," and I believe is listed -- but I will confirm this before we do anything with it.
Thanks for the clarifications/help to all who replied.

 

[wwhitney]

Never mind.

Cheers, Wayne

 

[infinity]

Never mind.

Cheers, Wayne

You read down a little further to (4).

 

[texie]

Thanks for the replies....
It is NOT tapping a tap... it's tapped right off the main feeder, coming from the 100A breaker protecting it.
Square raceway is not "Panduit," and I believe is listed -- but I will confirm this before we do anything with it.
Thanks for the clarifications/help to all who replied.

I think I follow now-you are tapping on the load side of a breaker.

If the raceway is listed surface raceway it should be fine. I was thinking of the finger type that is not a complete system.

 

[wwhitney]

You read down a little further to (4).

Yep, but not quickly enough to avoid your noticing.

So what is the purpose of 240.21(B)(1)(2)? And what is the import of the difference in wording between 240.21(B)(1)(2) and 240.21(B)(2)(2)?

Cheers, Wayne

 

[raider1]

Yep, but not quickly enough to avoid your noticing.

So what is the purpose of 240.21(B)(1)(2)? And what is the import of the difference in wording between 240.21(B)(1)(2) and 240.21(B)(2)(2)?

Cheers, Wayne

Wayne,

If the tap conductors originate within a switchboard etc and do not leave the switchboard the size of the tap conductor as related to the feeder conductors is not limited. That is what 240.21(B)(1)(2) is addressing.

Chris

 

[wwhitney]

So what is the purpose of 240.21(B)(1)(2)? And what is the import of the difference in wording between 240.21(B)(1)(2) and 240.21(B)(2)(2)?

Let me try to answer my own question. 240.21(B)(1)(2) (10' tap rule) says that the tap can only supply a single enclosure, but allows supplying multiple devices within that enclosure. 240.21(B)(2)(2) (25' tap rule) further says that the tap can only supply a single OCPD.

Or is there more to it?

Cheers, Wayne

 

[wwhitney]

If the tap conductors originate within a switchboard etc and do not leave the switchboard the size of the tap conductor as related to the feeder conductors is not limited. That is what 240.21(B)(1)(2) is addressing.

Hmm, I don't see what that has to do with 240.21(B)(1)(2), that is addressed in 240.21(B)(1)(4). What do you think of my previous post?

Cheers, Wayne

 

[infinity]

Let me try to answer my own question. 240.21(B)(1)(2) (10' tap rule) says that the tap can only supply a single enclosure, but allows supplying multiple devices within that enclosure. 240.21(B)(2)(2) (25' tap rule) further says that the tap can only supply a single OCPD.

Or is there more to it?

Cheers, Wayne

I see the single OCPD requirement for the 25' rule as the difference between the two. We once had a dimmer rack with the 10' tap rule that had only OCPD's on each individual 20 amp dimmer.