EMT with RT connectors on a outdoor service

[Electroplaxes]

I'm looking for any code references for and against that could help me. I have an exterior tap service 1000A to 400A/600A/600A. The trough is fed with schedule 80 PVC. Then it is piped from the trough down with EMT and RT connectors to a CT cabinets (top penetration). CTs are then connected with close nipples, locknuts and a myer hubs up into the discos. From the discos back down and out to the distribution panels via Schedule 40 PVC. NEC wise I don't think there is any violations. The reason for this post is some of the older guys in my shop say you can't use EMT for non-fused conductors. They are also stating it is required to have myer hubs in lieu of RT connectors. I think most of this is form a "that's the way we've always done it" view point. So now they're page turning trying to stick it to me. I don't some much care about them as I do the inspector, which is form around the same era as them. I'd like to be prepared if he raises the same questions. And above all if I am in violation I'd like to change it prior to a failed inspection and terminated wire. Thanks ahead of time.

 

[kwired]

I'm looking for any code references for and against that could help me. I have an exterior tap service 1000A to 400A/600A/600A. The trough is fed with schedule 80 PVC. Then it is piped from the trough down with EMT and RT connectors to a CT cabinets (top penetration). CTs are then connected with close nipples, locknuts and a myer hubs up into the discos. From the discos back down and out to the distribution panels via Schedule 40 PVC. NEC wise I don't think there is any violations. The reason for this post is some of the older guys in my shop say you can't use EMT for non-fused conductors. They are also stating it is required to have myer hubs in lieu of RT connectors. I think most of this is form a "that's the way we've always done it" view point. So now they're page turning trying to stick it to me. I don't some much care about them as I do the inspector, which is form around the same era as them. I'd like to be prepared if he raises the same questions. And above all if I am in violation I'd like to change it prior to a failed inspection and terminated wire. Thanks ahead of time.

It has been brought up many times on this site in the past that myers hubs are not listed for use with "straight threaded" fittings, which would include EMT fittings. They are listed for tapered threads like you will have on threaded RMC or IMC. See what those guys in your shop have to say about that.

I will not say they are never used and accepted with EMT fittings, just that is what the listing is.

 

[roger]

230.43 Wiring Methods for 600 Volts, Nominal, or Less.Service-entrance conductors shall be installed in accordance with the applicable requirements of this Code covering the type of wiring method used and shall be limited to the following methods:
(1) Open wiring on insulators
(2) Type IGS cable
(3) Rigid metal conduit
(4) Intermediate metal conduit
(5) Electrical metallic tubing
(6) Electrical nonmetallic tubing (ENT)
(7) Service-entrance cables
(8) Wireways
(9) Busways
(10) Auxiliary gutters
(11) Rigid nonmetallic conduit
(12) Cablebus
(13) Type MC cable
(14) Mineral-insulated, metal-sheathed cable
(15) Flexible metal conduit not over 1.8 m (6 ft) long or liquidtight flexible metal conduit not over 1.8 m (6 ft) long between raceways, or between raceway and service equipment, with equipment bonding jumper routed with the flexible metal conduit or the liquidtight flexible metal conduit according to the provisions of 250.102(A), (B), (C), and (E)
(16) Liquidtight flexible nonmetallic conduit

You might run into some trouble with the exposed schedule 40 PVC though

Roger

 

[kwired]

You might run into some trouble with the exposed schedule 40 PVC though

Roger

But only if subject to "physical damage". But that is entirely subject to interpretation. I can run schedule 80 and still subject it to physical damage in some instances. I have been in places where large machinery like payloaders are typically operating all the time and even RMC isn't going to stand up to the abuse, physical damage needs to be based on likely conditions. If it is based on "what if's" we wouldn't be allowed to install anything at all.

 

[roger]

But only if subject to "physical damage". But that is entirely subject to interpretation.

As is the case with most installations.

I can run schedule 80 and still subject it to physical damage in some instances.

The code allows that so you are good to go.

I have been in places where large machinery like payloaders are typically operating all the time and even RMC isn't going to stand up to the abuse, physical damage needs to be based on likely conditions.

And your point is? There will always be situations that are outside our best efforts.

If it is based on "what if's" we wouldn't be allowed to install anything at all.

Where did "what if" come to play? The OP didn't bring up a "what if" scenario, he stated he had exposed schedule 40 which is not listed for areas of physical damage and as you said, this is up to the AHJ's interpretation. If he had used schedule 80 he would be good regardless of the interprtation.

Roger

 

[kwired]

As is the case with most installations. The code allows that so you are good to go. And your point is? There will always be situations that are outside our best efforts.Where did "what if" come to play? The OP didn't bring up a "what if" scenario, he stated he had exposed schedule 40 which is not listed for areas of physical damage and as you said, this is up to the AHJ's interpretation. If he had used schedule 80 he would be good regardless of the interprtation.

Roger

IMO it is a "what if". Just because you run schedule 80 doesn't mean the installation is immune to physical damage, just is a little more durable than if it were schedule 40. What is likely to cause the damage is what is important. Like I said, even RMC is not immune to damage, just can take more abuse. If the abuse is at a likely level to damage RMC maybe alternate routing or additional protection is necessary.

Besides in the install in the OP you can run sch40 or sch 80 and I bet a fitting breaks before the raceway does anyway.

 

[roger]

IMO it is a "what if". Just because you run schedule 80 doesn't mean the installation is immune to physical damage, just is a little more durable than if it were schedule 40.

You're taking this outside the OP's question. We all know nothing is completely invincible but that is not the question. The OP is looking for code allowed methods, specifically EMT for use with unfused conductors, he then described his installation which seems to include some exposed schedule 40 PVC and schedule 40 could be called by the inspector unless it is identified for the use. Schedule 80 is identified for the use

I am sure there is no protection that will stand up to a nuclear blast which brings something up, you may want to check your auto insurance, I had a policy once that wouldn't pay to repaint my truck if the damage was due to nuclear fallout. :rant:

Roger

 

[kwired]

You're taking this outside the OP's question. We all know nothing is completely invincible but that is not the question. The OP is looking for code allowed methods, specifically EMT for use with unfused conductors, he then described his installation which seems to include some exposed schedule 40 PVC and schedule 40 could be called by the inspector unless it is identified for the use. Schedule 80 is identified for the use

I am sure there is no protection that will stand up to a nuclear blast which brings something up, you may want to check your auto insurance, I had a policy once that wouldn't pay to repaint my truck if the damage was due to nuclear fallout. :rant:

Roger

Well sorry, the initial comment about sch 40 really wasn't in the scope of the question either

But to some extent neither was my mentioning of myers hubs not being rated for use with "straight thread fittings", so we are even

Your quote from 230.43 is about as direct of an answer to the question as there can possibly be - I think.

 

[GoldDigger]

Well sorry, the initial comment about sch 40 really wasn't in the scope of the question either

But to some extent neither was my mentioning of myers hubs not being rated for use with "straight thread fittings", so we are even

Your quote from 230.43 is about as direct of an answer to the question as there can possibly be - I think.

Recognizing that if you use a wiring method such as #7 which does not require a raceway, you are fairly free to enclose it with almost anything you want for protection or appearance.

 

[kwired]

Recognizing that if you use a wiring method such as #7 which does not require a raceway, you are fairly free to enclose it with almost anything you want for protection or appearance.

You can also enclose a raceway for protection or appearance.

 

[tom baker]

EMT is not allowed for service entrance conductors in Washington with an exception for EMT installed before 1965, this is a state rule.

 

[kwired]

EMT is not allowed for service entrance conductors in Washington with an exception for EMT installed before 1965, this is a state rule.

What is the justification for this? Has it been the rule since 1965? If so they probably forgot what the justification was by now.

 

[Sierrasparky]

Is that for real.

 

[electrofelon]

EMT is not allowed for service entrance conductors in Washington with an exception for EMT installed before 1965, this is a state rule.

Partial correction. Emt is not allowed as a wiring method for service conductors inside a building. City of Seattle probably doesnt allow it anywhere for service conductors (in their replacement pages they have it crossed out - and say "reserved" - not sure what that means exactly)

I am baffled by the EMT restriction. Only thing I can think of is that they are concerned about its ability to carry service faults.

 

[joebell]

I agree with Roger you may have an issue with the schedule 40 PVC. If I'm reading your post correctly once you leave the disconnect, I'm assuming these are service disconnects, you are now dealing with an outside feeder. 225.20 requires mechanical protection of the conductors as stated by 230.50.


230.50 Protection Against Physical Damage.

(A) Underground Service-Entrance Conductors. Underground service-entrance conductors shall be protected against physical damage in accordance with 300.5.

(B) All Other Service-Entrance Conductors. All other service-entrance conductors, other than underground service entrance conductors, shall be protected against physical damage as specified in 230.50(B)(1) or (B)(2).

(1) Service-Entrance Cables.Service-entrance cables, where subject to physical damage, shall be protected by any of the following:


(1) Rigid metal conduit

(2) Intermediate metal conduit

(3) Schedule 80 PVC conduit

(4) Electrical metallic tubing

(5) Reinforced thermosetting resin conduit (RTRC)

(6) Other approved means

(2) Other Than Service-Entrance Cables. Individual open conductors and cables, other than service-entrance cables, shall not be installed within 3.0 m (10 ft) of grade level or where exposed to physical damage.

Exception: Type MI and Type MC cable shall be permitted within 3.0 m (10 ft) of grade level where not exposed to physical damage or where protected in accordance with 300.5(D). See related UL

You may get luck and the AHJ may approve the use of the schedule 40 Good Luck.

 

[kwired]

Five words in there leave this totally to the discretion of the inspector and or installer:

I agree with Roger you may have an issue with the schedule 40 PVC. If I'm reading your post correctly once you leave the disconnect, I'm assuming these are service disconnects, you are now dealing with an outside feeder. 225.20 requires mechanical protection of the conductors as stated by 230.50.


230.50 Protection Against Physical Damage.

(A) Underground Service-Entrance Conductors. Underground service-entrance conductors shall be protected against physical damage in accordance with 300.5.

(B) All Other Service-Entrance Conductors. All other service-entrance conductors, other than underground service entrance conductors, shall be protected against physical damage as specified in 230.50(B)(1) or (B)(2).

(1) Service-Entrance Cables.Service-entrance cables, where subject to physical damage, shall be protected by any of the following:


(1) Rigid metal conduit

(2) Intermediate metal conduit

(3) Schedule 80 PVC conduit

(4) Electrical metallic tubing

(5) Reinforced thermosetting resin conduit (RTRC)

(6) Other approved means

(2) Other Than Service-Entrance Cables. Individual open conductors and cables, other than service-entrance cables, shall not be installed within 3.0 m (10 ft) of grade level or where exposed to physical damage.

Exception: Type MI and Type MC cable shall be permitted within 3.0 m (10 ft) of grade level where not exposed to physical damage or where protected in accordance with 300.5(D). See related UL

You may get luck and the AHJ may approve the use of the schedule 40 Good Luck.

 

[joebell]

Five words in there leave this totally to the discretion of the inspector and or installer:

100% Correct