overhead electric service clearances

[mto12345]

Good morning

I am designing a carwash and normally we go underground to establish service from the Utility transformer under the wash tunnel (wet area) to the MDP in the Electrical room. However for this site the GC wants to go overhead from the transformer through the wash tunnel (wet area) to the MDP. Question is are there any clearance requirement (NEC?) I should be considering for the route. Obviously the conductors are in a Sch 40 PVC conduit.

 

[petersonra]

I'm not sure it matters whether the tunnel is wet area or not. I don't think that you're allowed to run service conductors through a building like that.

However if by overhead you mean outside the building above the roof line on a messenger that might be acceptable.

It really kind of depends on what you mean by overhead.

If it's going through the building and you put an ocpd at the point where it enters the building, then it's not service conductors anymore it's a feeder.

 

[4-20mA]

I think it used to be 13ft over driveways and 18ft over roadways iirc. Not sure what this would be considered. And not sure you can even go aerial through the building tunnel with your service though. I'll let these with more recent knowledge give you the advice you need.

 

[augie47]

It will likely end up being an AHJ call. We have had similar situations here and I agree with petersonra on the service conductors running "through a building" but locally it has been allowed since the wash bay was open and the conduit was visible up to the disconnect.

 

[mto12345]

I'm not sure it matters whether the tunnel is wet area or not. I don't think that you're allowed to run service conductors through a building like that.

However if by overhead you mean outside the building above the roof line on a messenger that might be acceptable.

It really kind of depends on what you mean by overhead.

If it's going through the building and you put an ocpd at the point where it enters the building, then it's not service conductors anymore it's a feeder.

I should have said from Utility Transformer to Discount switch then routes over the tunnel area(wet area) to MDP in the Electrical room. if i went underground (under tunnel) i would need a 24"-36" clearance, if I go overhead (over tunnel through the building) I need XXX? clearance.

 

[mto12345]

It will likely end up being an AHJ call. We have had similar situations here and I agree with petersonra on the service conductors running "through a building" but locally it has been allowed since the wash bay was open and the conduit was visible up to the disconnect.

I should have said from Utility Transformer to Discount switch then routes over the tunnel area(wet area) to MDP in the Electrical room. if i went underground (under tunnel) i would need a 24"-36" clearance, if I go overhead (over tunnel through the building) I need XXX? clearance.

 

[petersonra]

I should have said from Utility Transformer to Discount switch then routes over the tunnel area(wet area) to MDP in the Electrical room. if i went underground (under tunnel) i would need a 24"-36" clearance, if I go overhead (over tunnel through the building) I need XXX? clearance.

I not entirely sure what you mean by clearance. There is no specific rule about where you can run conduit in a building. I think you mentioned previously you were planning to run schedule 40 PVC which I believe is required to be run exposed only in areas where it is not subject to damage. I don't think anybody can tell you whether it's subject to damage where you plan to run it but if it's up 10 ft on the wall chances are it's not going to be hit by anything.

I think if you run rigid steel conduit under the floor you would only have to be 6 in deep.

 

[mto12345]

I not entirely sure what you mean by clearance. There is no specific rule about where you can run conduit in a building. I think you mentioned previously you were planning to run schedule 40 PVC which I believe is required to be run exposed only in areas where it is not subject to damage. I don't think anybody can tell you whether it's subject to damage where you plan to run it but if it's up 10 ft on the wall chances are it's not going to be hit by anything.

I think if you run rigid steel conduit under the floor you would only have to be 6 in deep.

OK thanks