(Another) Feeder Tap Question

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riversan

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Location
Nashville
Occupation
Contractor
Hello!
I am trying to get to the bottom of whether or not my existing electrical setup is a code violation and/or fire hazard. The folks I have consulted so far have been unable to convince me that there is in fact an issue and it largely seems to stem from a misunderstanding of feeder taps.

I have 200A service coming into a main panel. At the bottom of the main panel there are a set of pass-through lugs. These pass-through lugs are feeding a 125A sub-panel which is used for the HVAC. On this 125A panel there are 2x25A breakers which again are purely used for the HVAC system. The wire being used to connect the 125A sub-panel via the pass-through lugs are 2AWG rated for 100A. The distance between the main panel and the sub-panel is about 15ft and is enclosed in a protected raceway. I am being told that this is a code violation and a fire hazard as the wires are being fed 200A service and could create an overcurrent situation.

I believe my configuration would fall under Feeder tap rules. The updated 2020 NEC handbook has added language in 240.21(B) which now allows a feeder tap to be made directly to a lug or terminal. Since the distance of the conductor is greater than 10FT but less than 25FT then I would think per 240.21(2)(1) The wire would need to be rated for at least 200/3 = 66.67A. I believe my configuration also satisfies 240.21(2)(2) & 240.21(2)(3) -
(2) The tap conductors terminate in a single circuit breaker or a
single set of fuses that limit the load to the ampacity of the
tap conductors.
(This is the 125A sub-panel w/ 2x25A breakers ahead of the HVAC units)

(3) The tap conductors are protected from physical damage
by being enclosed in an approved raceway or by other
approved means
(The wire from the main panel to the sub-panel is in enclosed in a PVC raceway)

Both opinions are coming from folks at big box home service brands and have not been able to explain to me why my setup is incorrect, other than 200A into 100A = fire hazard. Hoping I could get a another opinion from this forum.

Main Panel
Sub-Panel

Thanks!
 
R

riversan

Member
Location
Nashville
Occupation
Contractor
Hi Xformer. Thanks for pointing me to that. So 240.21(B)(1)(1)b states:
Not less than the rating of the equipment containing an overcurrent device(s) supplied by the tap conductors - this would be the 125A sub panel?
or not less than the rating of the overcurrent protective device at the termination of the tap conductors - this would be the 2x25A breakers?

Since this is an OR I would think that my situation is to code given the 2x25A breakers sum to less than the 100A wire being used to feed these?
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Does your sub-panel have a main breaker?
If so, it can not be sized larger than the ampacity of your #2 conductors.
 
X

xformer

Senior Member
Location
Dallas, Tx
Occupation
Master Electrician
riversan said:
Hi Xformer. Thanks for pointing me to that. So 240.21(B)(1)(1)b states:
Not less than the rating of the equipment containing an overcurrent device(s) supplied by the tap conductors - this would be the 125A sub panel?
or not less than the rating of the overcurrent protective device at the termination of the tap conductors - this would be the 2x25A breakers?

Since this is an OR I would think that my situation is to code given the 2x25A breakers sum to less than the 100A wire being used to feed these?
Click to expand...
The Tap conductors must terminate in a OCPD.
 
J

jap

Senior Member
Occupation
Electrician
augie47 said:
Does your sub-panel have a main breaker?
Click to expand...

I just about posted the exact same question but then saw this,,

(This is the 125A sub-panel w/ 2x25A breakers ahead of the HVAC units)

Jap>
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I missed your picture link...
AS you quoted "terminate in a main breaker or fuse" which you do not have.


(and, as noted, separate your neutrals & equipment grounds)
 
R

riversan

Member
Location
Nashville
Occupation
Contractor
augie47 said:
I missed your picture link...
AS you quoted "terminate in a main breaker or fuse" which you do not have.


(and, as noted, separate your neutrals & equipment grounds)
Click to expand...
I am sorry for this likely very dumb question, but why don't the 2x25A breakers in the MLO sub-panel count as that? Are they not limiting the ampacity to be less than the tap conductor (50 < 100)?
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
riversan said:
I am sorry for this likely very dumb question, but why don't the 2x25A breakers in the MLO sub-panel count as that? Are they not limiting the ampacity to be less than the tap conductor (50 < 100)?
Click to expand...
Simply because the rule you quoted says "single" breaker...





riversan said:
Just to clarify, does this need to be done in the main panel or the sub-panel? Thanks
Click to expand...
Separated in any panel after the service panel.
 
R

riversan

Member
Location
Nashville
Occupation
Contractor
augie47 said:
Simply because the rule you quoted says "single" breaker...






Separated in any panel after the service panel.
Click to expand...
I understand now, thank you. Also @xformer messaged me on the side. The tap conductor is terminating to a set of lugs and not directly to an OCPD.
Is it right to say that, how its currently configured it's at least not a fire hazard? I know now it's clearly a code violation.

Lastly, how would I fix this? I believe someone told me adding a 40/50 quad breaker to the service panel and having that feed the MLO sub-panel would be the fix.. but then someone else said that is correct but that I don't have room for that in my service panel.. so they are suggesting a new panel!! 2 grand :(
 
R

riversan

Member
Location
Nashville
Occupation
Contractor
riversan said:
I understand now, thank you. Also @xformer messaged me on the side. The tap conductor is terminating to a set of lugs and not directly to an OCPD.
Is it right to say that, how its currently configured it's at least not a fire hazard? I know now it's clearly a code violation.

Lastly, how would I fix this? I believe someone told me adding a 40/50 quad breaker to the service panel and having that feed the MLO sub-panel would be the fix.. but then someone else said that is correct but that I don't have room for that in my service panel.. so they are suggesting a new panel!! 2 grand :(
Click to expand...
Could I instead change out the sub-panel to one which has a main breaker? Say something like this: https://www.lowes.com/pd/Eaton-100-...-On-Neutral-Load-Center-Value-Pack/1000551249

That way I could keep my existing service panel and conductors?
 
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