Original Post
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Hello and Happy Holidays to all !
Question:
What is the determining factor (or Code article) that governs the selection of a conductor insulation type that can be installed in a
raceway system that is environment-tight?
Example:
A listed-for-purpose waterproof raceway is installed in a wet location.
The only wire on-hand is THHN (dry or damp locations). Assuming integrity of the raceway, is it legal (and safe) to use this conductor as long as it is contained within the raceway system? What limitations or exceptions apply to a situation like this? Please mention any articles or sources that I should study to better understand this issue.
Thank you in advance for your help.
Bob
Followup from Bob (Original poster of the topic)
-------------------------------------
I would like to thank everyone for sharing their many years of expertise in the effort to clarify a muddy area of the Code.
The concensus appears to be:
Conductor Insulation ratings in Article 310.8 and the location definitions listed in Article 100 are the governing factors. Conductors and cables should be specified by the environment where the raceway is installed, regardless of the raceway's listed ability (and actual ability, since the two are not always the same) to exclude the surrounding environment.
This also implies that the conductor or cable insulation rating must be specified for the worst case environment that the raceway passes through while carrying a continuous, unspliced conductor run.
Also implied is that the conductor types could be changed by approved splicing methods prior to and after a change in the environment where the
raceway is installed.
An example:
A raceway that starts in a dry MCC, goes through an area subject to frequent washdowns, and terminates in another dry equipment room.
Are the following statements True or False???
1. Regardless of the raceway type, all conductors in this raceway must be listed for wet locations because they pass through a wet environment at some point during the continuous and unspliced run.
2. The conductors could start out rated for dry locations, change to wet location rating, and go back to dry location rating as long as splices are made in an approved manner and within a fixture listed for the purpose.
My purpose is not to pick nits, but to establish some easy to understand guidelines and standards for my work that will always yield a compliant and safe installation that I can be proud of.
Please let me know if I am interpreting these Articles correctly.
Once again, Thank you in advance for your help.
Bob G
-------------
Hello and Happy Holidays to all !
Question:
What is the determining factor (or Code article) that governs the selection of a conductor insulation type that can be installed in a
raceway system that is environment-tight?
Example:
A listed-for-purpose waterproof raceway is installed in a wet location.
The only wire on-hand is THHN (dry or damp locations). Assuming integrity of the raceway, is it legal (and safe) to use this conductor as long as it is contained within the raceway system? What limitations or exceptions apply to a situation like this? Please mention any articles or sources that I should study to better understand this issue.
Thank you in advance for your help.
Bob
Followup from Bob (Original poster of the topic)
-------------------------------------
I would like to thank everyone for sharing their many years of expertise in the effort to clarify a muddy area of the Code.
The concensus appears to be:
Conductor Insulation ratings in Article 310.8 and the location definitions listed in Article 100 are the governing factors. Conductors and cables should be specified by the environment where the raceway is installed, regardless of the raceway's listed ability (and actual ability, since the two are not always the same) to exclude the surrounding environment.
This also implies that the conductor or cable insulation rating must be specified for the worst case environment that the raceway passes through while carrying a continuous, unspliced conductor run.
Also implied is that the conductor types could be changed by approved splicing methods prior to and after a change in the environment where the
raceway is installed.
An example:
A raceway that starts in a dry MCC, goes through an area subject to frequent washdowns, and terminates in another dry equipment room.
Are the following statements True or False???
1. Regardless of the raceway type, all conductors in this raceway must be listed for wet locations because they pass through a wet environment at some point during the continuous and unspliced run.
2. The conductors could start out rated for dry locations, change to wet location rating, and go back to dry location rating as long as splices are made in an approved manner and within a fixture listed for the purpose.
My purpose is not to pick nits, but to establish some easy to understand guidelines and standards for my work that will always yield a compliant and safe installation that I can be proud of.
Please let me know if I am interpreting these Articles correctly.
Once again, Thank you in advance for your help.
Bob G