Sheet metal shop coil line apparatus transformer questions

[hhsting]

I have sheet metal shop with 1 arc welder , 1 resistant welder, 1 coil line apparatus

The coil line apparatus assembly drawing show transformer T3030K0023B Acme Transformer link below:

Link of the transformer:

Low Voltage Distribution Transformer - Three Phase, 480? - 240?120V, 30kVA | T3030K0023B | Acme Electric

Low Voltage Distribution Transformer - Three Phase, 480? - 240?120V, 30kVA

www.hubbell.com

The transformer internal wiring link:

https://hubbellcdn.com/technicaldrawing/T3030K0023B.pdf

It is wired in reverse has primary as 240/120V delta and secondary 480V delta and its 30kVA. Acme the manufacturer allows it.

The designer is saying the transformer is Not Separately derived, and it came with Coil line apparatus assembly has shop drawings proving transformer came with apparatus and so it is Not part of premise wiring. The transformer does Not need to be grounded per NEC 2014 Section 250.30 since it’s not part of premise wiring. NEC 2014 Section 450 exception no. 2 says NEC 2014 section 450 Not applicable to the transformer.



My questions:

1. NEC 2014 does Not mention for grounding 250.30 or separately derived definition premises served. Does the transformer need to be grounded NEC 2014?

2. Would NEC 2014 section 240.21 apply to this transformer?

3. Would NEC 2014 Section 450.1 exception no. 2 apply with this transformer?

4. Is the transformer separately derived or not?

 

[winnie]

My brain is too fuzzy to answer any of the code questions....but the transformer is very much an SDS.

Jon

 

[texie]

This is why we have NRTLs. Is the machine listed?

 

[augie47]

texie is 100% on target. IF the transformer is part of the NRTL listed equipment then NEC does not apply. At times as part of the "sale" the manufacturer will provide a transformer in order to sell the equipment in which case NEC applies including Arts. 250, 4550 & 240.

 

[hhsting]

texie is 100% on target. IF the transformer is part of the NRTL listed equipment then NEC does not apply. At times as part of the "sale" the manufacturer will provide a transformer in order to sell the equipment in which case NEC applies including Arts. 250, 4550 & 240.

I will double check with engineer designer. It could be that it came as part of sale manufacturer . I don’t know. The drawings show separate coil line apparatus, separate control cabinet and separate transformer standalone outside the apparatus and the cabinet. However their is shop drawings by Mestek Machinery which show the transformer and its wiring to the control cabinet.

 

[hhsting]

texie is 100% on target. IF the transformer is part of the NRTL listed equipment then NEC does not apply. At times as part of the "sale" the manufacturer will provide a transformer in order to sell the equipment in which case NEC applies including Arts. 250, 4550 & 240.

augie47 if the transformer is not internal to any listed equipment and it’s standalone outside of it would NEC applies including 250. 450 & 240?

 

[hhsting]

This is why we have NRTLs. Is the machine listed?

The transformer is Not internal to the coil apparatus. The drawings show separate coil line apparatus, separate control cabinet and separate transformer standalone outside the apparatus and the cabinet. However their is shop drawings by Mestek Machinery which show the transformer and its wiring to the control cabinet.

If the transformer is outside standalone the apparatus and the cabinet would it be premise wiring system or not?

 

[augie47]

Unless someone could show me otherwise, I would not consider it part of the equipment and enforce all the items you noted,. Did you determine if there was a NRTL listing on the equipment ?

 

[hhsting]

Unless someone could show me otherwise, I would not consider it part of the equipment and enforce all the items you noted,. Did you determine if there was a NRTL listing on the equipment ?

Not yet engineer was out. What I do have is attached two PDFs. One is wiring of transformer 30kVA, control cabinet breakers and the other shows coil apparatus, transformer control cabinet. Please see if it’s premise wiring system or not and also any NRTL. Would that tell you anything?



View attachment Response to Rev 5 and Data_7-7.pdf
View attachment Response to Rev 5 and Data_8-8.pdf

 

[augie47]

I'm out !

 

[hhsting]

I'm out !

I don’t follow? I am not allowed to ask what I did or not allowed to share?

 

[hhsting]

This is why we have NRTLs. Is the machine listed?

I don’t know if you or anyone can help here.
What I do have so far is attached two PDFs. One is wiring of transformer 30kVA, control cabinet breakers and the other shows coil apparatus, transformer control cabinet. Please see if it’s premise wiring system or not and also any NRTL. Would that tell you anything?
View attachment Response to Rev 5 and Data_7-7.pdf
View attachment Response to Rev 5 and Data_8-8.pdf

 

[winnie]

I don't see a fault current path on the 460V side, and I don't see fault detection.

As I read your original question, you were asking if you would be required to install a complete GEC connection from this transformer, with all of the annoying features such as finding a legit grounding electrode and the like.

I could imagine a situation where the transformer as part of a piece of equipment would not need a GEC and would not follow building wiring requirements, and would only have the necessary local EGC connections (equipment bonded to a terminal on the transformer secondary) so that faults could trip OCPD.

But your drawings show nothing, no EGC, no fault detection, nothing. Just a floating 480V delta. Methinks the supplier engineer doesn't really understand electricity.

-Jon

 

[hhsting]

I don't see a fault current path on the 460V side, and I don't see fault detection.

As I read your original question, you were asking if you would be required to install a complete GEC connection from this transformer, with all of the annoying features such as finding a legit grounding electrode and the like.

I could imagine a situation where the transformer as part of a piece of equipment would not need a GEC and would not follow building wiring requirements, and would only have the necessary local EGC connections (equipment bonded to a terminal on the transformer secondary) so that faults could trip OCPD.

But your drawings show nothing, no EGC, no fault detection, nothing. Just a floating 480V delta. Methinks the supplier engineer doesn't really understand electricity.

-Jon

Ok so it’s not shown on the drawing as it’s from supplier but the plans which I didn’t post which are PE stamp sign and seal do show EGC same size and incoming to the cabinet on 480V side.
Their is no system bonding jumper and GEC not on plans or on the attachment.

The EGC you mentioned is their my friend I made them put that alright on the plans alright. Ain’t no way they can go without that.

As my original question is of what is shown would be premise wiring system or not and would it require GEC, system bonding that needs to be solved.

 

[hhsting]

I don't see a fault current path on the 460V side, and I don't see fault detection.

As I read your original question, you were asking if you would be required to install a complete GEC connection from this transformer, with all of the annoying features such as finding a legit grounding electrode and the like.

I could imagine a situation where the transformer as part of a piece of equipment would not need a GEC and would not follow building wiring requirements, and would only have the necessary local EGC connections (equipment bonded to a terminal on the transformer secondary) so that faults could trip OCPD.

But your drawings show nothing, no EGC, no fault detection, nothing. Just a floating 480V delta. Methinks the supplier engineer doesn't really understand electricity.

-Jon

Please disregard previous post. Please see revised below. Some of your questions were not answered previously.

Transformer shown is outside the cabinet, coil apparatus not internal part of equipment. How do you see it as part of equipment?

Ok so it’s not shown on the drawing as it’s from supplier but the plans which I didn’t post which are PE stamp sign and seal do show EGC same size and incoming to the cabinet on 480V side.
Their is no system bonding jumper, fault detection and GEC not on plans or on the attachment.

The EGC you mentioned is their my friend I made them put that alright on the plans alright. Ain’t no way they can go without that.

As my original question is of what is shown would be premise wiring system or not and would it require GEC, system bonding that needs to be solved. Also is fault detection required need to be solved. However if it’s not premise wiring system then why care about EGC as you say NEC won’t apply so how can one enforce it?

 

[winnie]

Transformer shown is outside the cabinet, coil apparatus not internal part of equipment. How do you see it as part of equipment?

I didn't intend to imply that I'd formed an opinion on that point. I am not making a call on it being part of equipment vs being part of building wiring. I was stating a hypothetical that _if_ it were part of equipment it might not need to meet all of the NEC requirements, but I would still expect to see a fault current path (system bonding jumper) or ground detection.

Ok so it’s not shown on the drawing as it’s from supplier but the plans which I didn’t post which are PE stamp sign and seal do show EGC same size and incoming to the cabinet on 480V side.
Their is no system bonding jumper, fault detection and GEC not on plans or on the attachment.

I also mis-spoke when I said I didn't see an EGC. I meant that I didn't see a bond from the transformer secondary to non-current carrying metal, no system bonding jumper.

As my original question is of what is shown would be premise wiring system or not and would it require GEC, system bonding that needs to be solved. Also is fault detection required need to be solved. However if it’s not premise wiring system then why care about EGC as you say NEC won’t apply so how can one enforce it?

Even if NEC doesn't apply, good engineering practice should! An ungrounded 480V delta without ground fault detection is IMHO bad practice, even if the NEC does not apply. If one of the 480V supply leads from this transformer comes in contact with the metal frame of the apparatus, what happens? Now what happens when the second fault occurs. If there is a 'restriking fault' (where you have intermittent contact because of vibration, what happens?

Physically you have a separately derived system. I cannot answer the _legal_ question of 'do the NEC rules for SDSs apply', but the physics doesn't change.

-Jon

 

[hhsting]

I didn't intend to imply that I'd formed an opinion on that point. I am not making a call on it being part of equipment vs being part of building wiring. I was stating a hypothetical that _if_ it were part of equipment it might not need to meet all of the NEC requirements, but I would still expect to see a fault current path (system bonding jumper) or ground detection.



I also mis-spoke when I said I didn't see an EGC. I meant that I didn't see a bond from the transformer secondary to non-current carrying metal, no system bonding jumper.



Even if NEC doesn't apply, good engineering practice should! An ungrounded 480V delta without ground fault detection is IMHO bad practice, even if the NEC does not apply. If one of the 480V supply leads from this transformer comes in contact with the metal frame of the apparatus, what happens? Now what happens when the second fault occurs. If there is a 'restriking fault' (where you have intermittent contact because of vibration, what happens?

Physically you have a separately derived system. I cannot answer the _legal_ question of 'do the NEC rules for SDSs apply', but the physics doesn't change.

-Jon

What about GEC connection 250.32(B)?

Also see Premise Wiring (system) definition section 100 it does Not include internal wiring to similar equipment but would include wiring outside equipment such as between xfmr and control cabinet so NEC would apply no? I mean transformer is outside between cabinet and coil apparatus? If you don’t have opinion can anyone else please have opinion here?

 

[winnie]

Like I said, I am not making a call on this being premises wiring or not.

If this is premises wiring then a GEC is required.

Jon

 

[electrofelon]

I would not let them try to trick you into believing this is part of the equipment so not subject to the NEC. NEC 110.3 requires equipment to be approved by the AHJ. Listing is often what makes something approved. If this thing isn't listed AS SET UP, then I call BS on their claim.

 

[hhsting]

I would not let them try to trick you into believing this is part of the equipment so not subject to the NEC. NEC 110.3 requires equipment to be approved by the AHJ. Listing is often what makes something approved. If this thing isn't listed AS SET UP, then I call BS on their claim.

The way I understand it is that one equipment can have NRTL such generator breaker switchboard transformer etc etc.

The one I have has separate coil apparatus machine equipment, separate control cabinet, separate Acme transformer outside control cabinet and outside coil apparatus machine. They are Not all internal. Can bunch of separate equipments put together as system can they have NRTL? I don’t get that part