Do I need a ground conductor in EMT?

[skeshesh]

As a contractor who bid the job to specs and didn't get the job, I would be very angry if I found out the other EC didn't follow specs. In fact, I would report it.

I absolutely agree. The contractor should have some ethics; I've dealt with a few contractors that lowball bids as far as %50 lower than the cost estimate and try to cut corners. Bottom line is it makes everyone's life more difficult.

Also, if the local laws require inspection per spec then it should be done. There are plenty of local regulations all over the place that can make any profession more complicated - that doesn't mean the regulation has no value.

 

[jghrist]

:grin:

It's never a problem on a design-bid-build job. It's when it's a design-build job and arguments ensue about nitpicking costs of things. It's amazing what some people will try to tell you some things cost to build.

If it's in the bid documents of the design-build job, then there shouln't be any question. If it isn't covered in the bid documents, then the contractor needs to make things very clear to the engineer how it was bid. Or make sure that the engineer makes the plans with minimum Code compliant design.

 

[bluesmoke...oops]

If it's in the bid documents of the design-build job, then there shouln't be any question. If it isn't covered in the bid documents, then the contractor needs to make things very clear to the engineer how it was bid. Or make sure that the engineer makes the plans with minimum Code compliant design.

Yeah it's been my experience that doesn't occur. You get the stumble through or they wait until you are done and have met the bid docs, then start getting mad cause your design didn't meet their unshared vision, and you are robbing their kids college funds cause of what it's going to cost, etc.

I've been told that apparently a 8x8x8 basic shed on a concrete pad with two lights, and a couple receps to house a rack with inverters costs 100k to build. I'm thinking of subbing it out from the contractor with the rest of the EEs here for 90k and building it for him this weekend.

 

[iwire]

Yeah it's been my experience that doesn't occur. You get the stumble through or they wait until you are done and have met the bid docs, then start getting mad cause your design didn't meet their unshared vision, and you are robbing their kids college funds cause of what it's going to cost, etc.

I've been told that apparently a 8x8x8 basic shed on a concrete pad with two lights, and a couple receps to house a rack with inverters costs 100k to build. I'm thinking of subbing it out from the contractor with the rest of the EEs here for 90k and building it for him this weekend.

This can be fixed very easily, the person doing the specifying or one of their representatives should be visiting the job and looking for compliance. That is how it is done here.

To expect the building official to do that, or for it just to happen because it is in the spec is in my opinion ridiculous.

 

[bluesmoke...oops]

I'm talking about during the design phase. My experience is that you have to twist arms to get details.

 

[dana1028]

Yep. In some places the engineers specs are enforced by the inspector. Local laws vary.

Actually, as an inspector, I am required to follow engineers specs [I'm making an assumption that the specs are part of a set of plans that have gone through the plan check/permit process].

 

[jumper]

Actually, as an inspector, I am required to follow engineers specs [I'm making an assumption that the specs are part of a set of plans that have gone through the plan check/permit process].

Agreed. I was referring to such when I stated my opinion

 

[peter d]

Actually, as an inspector, I am required to follow engineers specs [I'm making an assumption that the specs are part of a set of plans that have gone through the plan check/permit process].

So then you are now a "specification enforcer", not a code enforcer. Often specs go well above and beyond the NEC. I don't understand how this is even legal for a gov't official to enforce things that are not part of a code standard. I know it's required of you in those areas of the country as has been mentioned, but I question the legality of it.

 

[Dennis Alwon]

So then you are now a "specification enforcer", not a code enforcer. Often specs go well above and beyond the NEC. I don't understand how this is even legal for a gov't official to enforce things that are not part of a code standard. I know it's required of you in those areas of the country as has been mentioned, but I question the legality of it.

Peter, the plans go thru a planning dept process and are accepted as drawn. If you change that process then you could get hit on it. This is not an NEC thing but rather what the planning dept accepted. Why should they care if it is legal?-- I don't know. But it does help those who legitimately bid the plans as drawn.

 

[conmgt]

This engineer also specified 4" conduit for (4) 500 MCM and a #3 GND. The conduit is a straight run of 54". Should I not be able to use 3 1/2 or 3"? Fill tables allow (5) 500 MCM in 3"

Should I not be able to use Al XHHW instead of copper is sized right e.g. 250 MCM in place of 3/0 Cu. Have you priced Cu MCM lately?

 

[iwire]

If you bid the job based on specs you cannot just decide not to meet the specs.

The customer hired the engineer for a reason .... to design and specify the type of electrical system they are getting. If they wanted the electrician to make these decisions they would not have specs.

You can always ask to make substitutions and they may say OK but they may also ask for a credit for the value that the job was reduced

 

[iwire]

Peter, the plans go thru a planning dept process and are accepted as drawn. If you change that process then you could get hit on it. This is not an NEC thing but rather what the planning dept accepted. Why should they care if it is legal?-- I don't know. But it does help those who legitimately bid the plans as drawn.

Dennis, I think you are missing the point.


Neither Peter or I is saying no one should be enforcing the specs, I firmly believe someone should enforce the specs. I just don't think that should be the municipal inspector. I do understand that is how it is done in many areas.

On the jobs I used to work we would get vistis at any time by the Engineer or their representives, they might stop by quick or they might watchj us or most of the day. Unlike the electrical inspector we would never know when an engineer would be stoping by. Or on other jobs like a national chain they often asign a full time representive on the job that knows the specs quite well and will address any diveation as soon as they see it.

In truth I feel we are watched over much more closely than those areas that simple rely on the EI.

 

[Awg-Dawg]

This engineer also specified 4" conduit for (4) 500 MCM and a #3 GND. The conduit is a straight run of 54". Should I not be able to use 3 1/2 or 3"? Fill tables allow (5) 500 MCM in 3"

Should I not be able to use Al XHHW instead of copper is sized right e.g. 250 MCM in place of 3/0 Cu. Have you priced Cu MCM lately?

It has been my experience that if you can show that you need to reduce your raceway(space, conflicts,etc) it has never been a problem.

Now as far as the AL over Cu, Good luck.......

 

[bluesmoke...oops]

Yeah talk to the engineer and make sure they weren't putting in oversize pipe for future expansion that you may not know about.

 

[iwire]

It has been my experience that if you can show that you need to reduce your raceway(space, conflicts,etc) it has never been a problem.

I agree, here is a job where I asked if I could reduce the 4" RMC specified to 3" EMT. It was a rack of five and I had to run it through tight suspended ceiling, I was able to reduce the size of the rack by quite bit.

The engineer did ask me to provide the fill calculations and pulling tension calculations to show that this was an acceptable reduction.

 

[don_resqcapt19]

...
The engineer did ask me to provide the fill calculations and pulling tension calculations to show that this was an acceptable reduction.

Bob,
Do you have a pulling calculation that shows the pulling tension changes with raceway size? I have never seen one that does that. I agree that the reduced conduit size will often mean the bending radius is smaller and that the sidewall pressure will go up, but have not seen anything that says the pulling tension goes up as long as the raceway is code legal for the number and size of conductors being installed.

 

[iwire]

Bob,
Do you have a pulling calculation that shows the pulling tension changes with raceway size?

No, but regardless that was his request.

So I provided him with the info and references that I used to make the calculations.

 

[peter d]

Dennis, I think you are missing the point.


Neither Peter or I is saying no one should be enforcing the specs, I firmly believe someone should enforce the specs. I just don't think that should be the municipal inspector. I do understand that is how it is done in many areas.

On the jobs I used to work we would get vistis at any time by the Engineer or their representives, they might stop by quick or they might watchj us or most of the day. Unlike the electrical inspector we would never know when an engineer would be stoping by. Or on other jobs like a national chain they often asign a full time representive on the job that knows the specs quite well and will address any diveation as soon as they see it.

In truth I feel we are watched over much more closely than those areas that simple rely on the EI.

Precisely.

Furthermore, on a large job, how could an EI even remotely enforce the multitude of specs? That would take some serious investigation that I doubt he even has time for. That's why, as Bob said, the engineer or building rep is far more able and qualified to see that job specs are enforced.

 

[qcroanoke]

If you bid the job based on specs you cannot just decide not to meet the specs.

The customer hired the engineer for a reason .... to design and specify the type of electrical system they are getting. If they wanted the electrician to make these decisions they would not have specs

Well said Bob.
The specs. are there for a reason. If you don't want to work by the specs. then take exception to the parts you don't want to meet, or can't meet, or if you already exceed the specs. in that area.

 

[dana1028]

Peter, the plans go thru a planning dept process and are accepted as drawn. If you change that process then you could get hit on it. This is not an NEC thing but rather what the planning dept accepted. Why should they care if it is legal?-- I don't know. But it does help those who legitimately bid the plans as drawn.

Thank you Dennis - as an inspector we are required to inspect to the approved set of plans even if those specs exceed code. Often times planning makes requests for the plans [structural, life safety, fire code, etc.] - as an inspector in the field we have no specific knowledge of all the notes and requirements that were required for planning. Also an engineer [electrical] might be making requirements above the code for reasons we are not aware of - we don't know his [engineer's] reasoning - but we must inspect to his design.