Transformer secondary raceway and conductors

[Dsg319]

Secondary conductors routed in 1.5”LFMC (sealtight) and terminate into the disconnect through concentric knock outs that go up 2”. So there is still one left.

At a minimum the line side from transformer to disconnect needs a bonding bushing/jumper on at least one side correct.

The voltage is 240/120 delta high leg. The reason you only see two conductors is because it is feeding a single phase panel board. Yes I know what a waste but

 

[augie47]

With LFMCs limited capacity as a grounding means it could not be used as the SSBJ so I see no reason for a bond bushing

 

[Dsg319]

With LFMCs limited capacity as a grounding means it could not be used as the SSBJ so I see no reason for a bond bushing

Yes I pulled the correct size ssbj in the LFMC but you are saying you see no reason to have a bond bushing even though it terminates into a concentric knock out? I guess only if it was over 250volts to ground and enclosure not rated for grounding over that?

 

[Dsg319]

With LFMCs limited capacity as a grounding means it could not be used as the SSBJ so I see no reason for a bond bushing

I see what you’re saying now like using EMT or rigid raceway as the SSBJ.

So even if it was rigid conduit with a wire type SSBJ would I still need a bonding bushing/jumper since it’s terminating into K/O.

 

[augie47]

I see what you’re saying now like using EMT or rigid raceway as the SSBJ.

So even if it was rigid conduit with a wire type SSBJ would I still need a bonding bushing/jumper since it’s terminating into K/O.

IMO, no, if the conduit was terminated in a 250.97 prescribed manner.

 

[infinity]

No bonding bushing is required for less than 250 volts to ground.

 

[Dsg319]

No bonding bushing is required for less than 250 volts to ground.

See I thought this but I thought maybe it was different since it was secondary conductors off a transformer before any OCPD

What is the exact code section to clarify.

 

[infinity]

See I thought this but I thought maybe it was different since it was secondary conductors off a transformer before any OCPD

What is the exact code section to clarify.

Augie gave the code section in post #5. {250.97} Additional bonding around concentric or eccentric KO's begins above 250 volts to ground. The fact that there is a SDS involved is irrelevant although many think that a transformer gets wired like a service.

 

[Dsg319]

I’d assume even a disconnect that is suitable for use as service equipment has concentric k/o that are listed for a reliable bonding connection but I couldn’t find any thing that said it.

 

[Dsg319]

Augie gave the code section in post #5. {250.97} Additional bonding around concentric or eccentric KO's begins above 250 volts to ground. The fact that there is a SDS involved is irrelevant although many think that a transformer gets wired like a service.

Thanks I just did look through it. I guess I was one of the victims who fell into the SDS wired like a service hype.

Thanks guys.

 

[don_resqcapt19]

I’d assume even a disconnect that is suitable for use as service equipment has concentric k/o that are listed for a reliable bonding connection but I couldn’t find any thing that said it.

As far as I know it is pretty much the smaller boxes that are so listed. Have not seen a disconnect or panelboard with that listing

 

[infinity]

I’d assume even a disconnect that is suitable for use as service equipment has concentric k/o that are listed for a reliable bonding connection but I couldn’t find any thing that said it.

You won't find any such listing. Concentric, eccentric, or full KO a service raceway would require bonding beyond a standard locknut. The bonding method may vary based on the type of KO. A concentric or eccentric KO would require a bonding bushing. A full KO could use a bonding bushing, bonding locknut, or a bonding wedge.

 

[augie47]

Rob, am I correct in my thinking that as long as he doesn't have concentric or eccentric ko's then he would not need bond bushings if terminated as listed in the Exception (250.97) since he has a wire type SSBJ and doesn't need the conduit to serve as a SSBJ but we are only bonding the conduit ?

 

[infinity]

Rob, am I correct in my thinking that as long as he doesn't have concentric or eccentric ko's then he would not need bond bushings if terminated as listed in the Exception (250.97) since he has a wire type SSBJ and doesn't need the conduit to serve as a SSBJ but we are only bonding the conduit ?

The conduit is bonded by the connector on the LFMC. Since it's less than 250 volts to ground nothing else is required to bond the raceway beyond the locknut. You're correct that the raceway cannot serve as the SSBJ.

 

[augie47]

I did not word my question well..........
IF he used EMT between the transformer and the disconnect and installed a wire type SSBJ bonded to the disconnect, and the conduit was terminated at the disconnect per the exception in 250.97 (no concentric & double lockout) thus bonded, there would be no need for a grounding bushing, correct ?

 

[Tulsa Electrician]

In the pic, the split bolt caught my attention.

 

[augie47]

In the pic, the split bolt caught my attention.

along with the bonded neutral-SSBJ mix ... but I stuck to the question at hand

 

[Dsg319]

In the pic, the split bolt caught my attention.

Yes it’s just a second main bond to satisfy my OCD LOL. The main bond jumper is this disconnect is actually the green screw from neutral bar to the can. Then the #2THHN that is directly bonded to the neutral is the GEC. So the ECG gets its bond from the case which I didn’t like, so therefor I split bolt EGC to neutral.

 

[Dsg319]

along with the bonded neutral-SSBJ mix ... but I stuck to the question at hand

Yes the neutral is bonded here I know it looks funny. Lol.

But neutral is floating in the transformer.

 

[ActionDave]

Yes the neutral is bonded here I know it looks funny. Lol.

But neutral is floating in the transformer.

That's the way I was taught and prefer to do it that way. It used to be there was not any good place to put the bonding jumper, both EGCs and the GEC in the transformer.