Question on article 555

[RICHRICH36]

Hello, I am drawing a complete blank and maybe reading too deep in to this. In reference to article 555.9 (2011) the code states:


All electrical connections shall be located at least
305 mm (12 in.) above the deck of a fixed pier but not below
the electrical datum plane.

This is contradictory. To me, it says has to be 12 inches above the deck but not below the electric datum plane. How can it be both? I have never seen wiring above the deck. Am I missing something here?

 

[Dennis Alwon]

They are talking about the electrical connection. If the pier is low and 12" is below the datum plane then you must be higher. I am sure most piers that is not an issue.

 

[ceb58]

Hello, I am drawing a complete blank and maybe reading too deep in to this. In reference to article 555.9 (2011) the code states:


All electrical connections shall be located at least
305 mm (12 in.) above the deck of a fixed pier but not below
the electrical datum plane.

This is contradictory. To me, it says has to be 12 inches above the deck but not below the electric datum plane. How can it be both? I have never seen wiring above the deck. Am I missing something here?

If that plane as described in 555.2 (1)&(2) is greater than the 12" it must be installed above the plane. You datum plane could be 18 " above the deck so you would install above the 18"

 

[RICHRICH36]

Well maybe I am mis-reading but I am assuming "electrical connections" would include for instance, path lighting. To me it reads that the connection would need to be 12" above the deck.

 

[ceb58]

Well maybe I am mis-reading but I am assuming "electrical connections" would include for instance, path lighting. To me it reads that the connection would need to be 12" above the deck.

And that would be correct

 

[RICHRICH36]

Hello, I am drawing a complete blank and maybe reading too deep in to this. In reference to article 555.9 (2011) the code states:


All electrical connections shall be located at least
305 mm (12 in.) above the deck of a fixed pier but not below
the electrical datum plane.

This is contradictory. To me, it says has to be 12 inches above the deck but not below the electric datum plane. How can it be both? I have never seen wiring above the deck. Am I missing something here?

If I take just the first line, all connections shall be located at least 12" above the deck. This is where I am getting hung up. I understand that it is possible for the deck to be below datum plane which the second half would require "but not below the electrical datum plane"

 

[RICHRICH36]

ceb58, correct me if I am wrong but wouldnt dock pedestals would have to be 12" above the deck. There is single point "connections" in the base.

 

[ceb58]

ceb58, correct me if I am wrong but wouldnt dock pedestals would have to be 12" above the deck. There is single point "connections" in the base.

Look at 555.11

 

[RICHRICH36]

Ahhhhh, you got me on the pedestal. Bad example. I am still curious as to the lighting. Am I correct in my interpretation that connections need to be 12" above the deck for lighting? That means that on a dock / pier with patch lighting you would see pvc ran 12" above? Sorry if I am misinterpreting this but I cant seem to get past that one sentence.

 

[Dennis Alwon]

Ahhhhh, you got me on the pedestal. Bad example. I am still curious as to the lighting. Am I correct in my interpretation that connections need to be 12" above the deck for lighting? That means that on a dock / pier with patch lighting you would see pvc ran 12" above? Sorry if I am misinterpreting this but I cant seem to get past that one sentence.

The code says electrical connection so it should apply to lighting- 12" above the deck or more if that 12" is in the datum plane. And yes you will see the pvc

 

[ceb58]

Ahhhhh, you got me on the pedestal. Bad example. I am still curious as to the lighting. Am I correct in my interpretation that connections need to be 12" above the deck for lighting? That means that on a dock / pier with patch lighting you would see pvc ran 12" above? Sorry if I am misinterpreting this but I cant seem to get past that one sentence.

The code says electrical connection so it should apply to lighting- 12" above the deck or more if that 12" is in the datum plane. And yes you will see the pvc

If you were wanting to put path lighting on the post you can run your pvc below and turn up into the box that is 12" above the deck. Its the connection that must comply.

 

[dicklaxt]

I think (memory recall here) that the datum line is an established line 2' above the high tide waterline,so go from there. I helped on a pier a few years back and it's sketchy but I believe thats what we used..so in reference to the OP the datum line would be below the deck and probably is in most all cases,,,,,,why would you want a deck below the high tide line........

dick

 

[Dennis Alwon]

If you were wanting to put path lighting on the post you can run your pvc below and turn up into the box that is 12" above the deck. Its the connection that must comply.

Sure but the pvc will be visible those 12"-- I thought that was what the OP was asking.

 

[ceb58]

Sure but the pvc will be visible those 12"-- I thought that was what the OP was asking.

I thought he was referring to the full run ?????

 

[RICHRICH36]

I was referring particularly to the connections. i.e. pathway lighting. I take it to understand that there is no way possible to have a code compliant installation of a path light that would be mounted directly on to a deck unless this lighting had some sort of pedestal that would raise above 12".

Thanks for the input. Sometimes even though it is in black and white I still try to understand the concept behind it.

 

[dicklaxt]

That is confusing as I have seen many pier lights that were surface and/or recessed in the deck itself,,,,it will be interesting to read the arguments on this one

dick

 

[RICHRICH36]

dicklaxt, that is the exact reason for my question. I have seen it so much that I kept telling myself that I have to be overlooking something in NEC for it to be allowed. Hence the reason for the post.