Thread: when is conduit required?

Single family dwelling with 200 amp square D QO panel. Typical cinder block and wood frame construction. MEP engineer specified conduit on level II remodel. I am not sure that I understand this. Why cant the non-exposed circuits be romex cable? I understand that all exposed, buried, or exterior wire should encased, but is it really necessary to use conduit for interior circuits. Thanks.

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A lot depends on local codes.

City of Miami, Florida. Any guidance would be appreciated.

Originally Posted by dave bourne

Single family dwelling with 200 amp square D QO panel. Typical cinder block and wood frame construction. MEP engineer specified conduit on level II remodel. I am not sure that I understand this. Why cant the non-exposed circuits be romex cable? I understand that all exposed, buried, or exterior wire should encased, but is it really necessary to use conduit for interior circuits. Thanks.

Originally Posted by dave bourne

City of Miami, Florida. Any guidance would be appreciated.

The applicable code is the Florida Building Code, Residential.

You have answered your own question, but do not realize it ...

"MEP engineer specified conduit on level II remodel."

"I am not sure that I understand this."

What is to understand?

That person was hired by the owner to design that portion of the job, they are the engineer, their client wants the work done that way, either because the client trusts the engineer's recommendations or because the client specified conduit.

Remember, the code is MINIMUM ... engineers can design anything above that minimum level that their client wants. Apparently the client wants BETTER THAN MINIMUM ... as such - what is there to understand?

Other than the client and the engineer want, and EXPECT, higher quality work.

Jerry,
You are correct and I appreciate that the engineer can design above the standard, but my motive in posting here is that I am trying to figure out what is required. I am the homeowner and cant grasp why he specified this. I am trying to reconcile the difference between required and desired. Is this required in Florida or is it just good sense? Thanks

Originally Posted by dave bourne

Jerry,
You are correct and I appreciate that the engineer can design above the standard, but my motive in posting here is that I am trying to figure out what is required. I am the homeowner and cant grasp why he specified this.

If you are the owner and you hired the engineer, if you want NM cable, tell them, if they can't convince you of the benefits of conduit and won't do what you want, you should look for another engineer.

I am trying to reconcile the difference between required and desired.

I can't tell you what you should desire, that depends on you and your pocket book, but conduit has advantages and drawbacks, NM cable has advantages and drawbacks, but conduit will give a more professional installation which will last longer and through which you can replace wiring simply by pulling out the old and pulling in the new. Size the conduit properly and you already have a way to add circuits built-in. However, if you want to add circuits or outlets beyond the locations of the conduit, you would either extend the system with NM cable fished in the walls or open walls up to install conduit within the wall.

Is this required in Florida or is it just good sense? Thanks

The only requirements in Florida and any other state are the codes, and the codes are "minimum" requirements.

This is what the NEC has to say about itself in acknowledging that even the NEC, as tough and wicked as some contractors think it is, is only a "minimum" standard: (bold, italics and underlining are mine)
- 90.1 Purpose.
- - (A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.
- - (B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.

In other words, doing the minimum which is allowed in the NEC does not mean it will result in an efficient or even adequate electrical system.

NM cable is an allowed wiring method - it is used all over by residential contractors and builders, and by others too.

Conduit results in a longer life system in which failures can be readily replaced. I.e., a damaged NM cable is difficult to repair or replace, the conduit wiring would first and foremost suffer less damage, and the wiring can be pulled out and replaced if needed. Conduit also costs more, probably a lot more.

Depends on the budget and other wants and needs that you gave your engineer as a guideline to use.

How large is the house and what is the cost of the project?

Jerry,
Thanks for the response. This a 2,400 sq ft home, but a huge nightmare. The architect has overbilled me and gone bankrupt. The plans I have are 100% over budget and seven months late (my family is living in a rental). I am trying to piece this back together.
The MEP seems to be overbuilt. Which has its advantages, but when this is so off track, I need to take charge and figure out how to get this on a path to resolution. Conduit will substantially inflate the electrical costs. While there are benefits, right now the biggest benefit is finishing this job so that I can get my family back into their home.
If conduit is not required, I would like to ask the MEP to delete.
On another subject, the structural engineer specd lots of unrequired strong-ties, but these are not substantially increasing the costs and the benefit is that I can get a higher wind mitigation. To me, this makes sense. Minimal addtional cost and time, large payoff.
Back to the conduit, large addtional costs, and no immediate benefit. As long as the gauge wire is correct for the intended use, both NM and conduit will perform the same.
Thanks again for your input. I think that solution is to go back to the MEP and ask him to remove. Appreciate the insight

Originally Posted by dave bourne

Jerry,
Thanks for the response. This a 2,400 sq ft home, but a huge nightmare. The architect has overbilled me and gone bankrupt. The plans I have are 100% over budget and seven months late (my family is living in a rental). I am trying to piece this back together.
The MEP seems to be overbuilt. Which has its advantages, but when this is so off track, I need to take charge and figure out how to get this on a path to resolution. Conduit will substantially inflate the electrical costs. While there are benefits, right now the biggest benefit is finishing this job so that I can get my family back into their home.
If conduit is not required, I would like to ask the MEP to delete.
On another subject, the structural engineer specd lots of unrequired strong-ties, but these are not substantially increasing the costs and the benefit is that I can get a higher wind mitigation. To me, this makes sense. Minimal addtional cost and time, large payoff.
Back to the conduit, large addtional costs, and no immediate benefit. As long as the gauge wire is correct for the intended use, both NM and conduit will perform the same.
Thanks again for your input. I think that solution is to go back to the MEP and ask him to remove. Appreciate the insight

Tell the MEP that you want code minimum and nothing more. There is nothing wrong with NM cable when properly installed.

Local codes are key, but the goal is protecting the wires from possible physical damage. There are means of protection other than conduit like framing, running boards, etc. Check w/ the AHJ on alternatives. While exploring that, tell him/her how much you love um and once you have convinced um safety is your priority see, if the conduit thing can go away altogether

Originally Posted by Robert Meier

Tell the MEP that you want code minimum and nothing more. There is nothing wrong with NM cable when properly installed.

DO NOT TELL YOUR MEP ENGINEER YOU WANT CODE MINIMUM ...

You could tell them you want NM cable as that is allowed by code and that you feel that is adequate for your needs - after all, YOU are the boss, replace the MEP engineer if they cannot do what you want.

Sorry to hear about the architect and over budget troubles, just don't let that make you think in terms of minimums. I like your thinking about more straps is better, and it is, but just as importantly is the installation of each and every strap. Otherwise you may end up with twice as many straps, but half of them are not really doing anything, in which case you paid twice as much for nothing gained.

Question out of curiosity: Is the conduit metal or PVC? I hope the answer will be PVC.