Tap rules and temporary installations

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sasorikage

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Hello, I have a question in regards to the tap rules. I can not find anything that exempts the tap rules in a temporary installation. Is this correct? Or are there exceptions that I am not aware of. Any help is greatly appreciated. The installation is feeding multi equipment in the field from a service disconnect the distance to the equipment is over 80 feet. Their current installation is a gutter on the power skid from which they tap to conductors sized to the various equipment loads. I feel there needs to be a disconnect sized properly at the service since it exceeds the lengths on the tap rules.Thanks again.
 
Article 590 says the rest of the code rules apply unless specifically modified in 590. The overcurrent protection rules apply to Article 590 applications.
590.2 All Wiring Installations
(A) Other Articles. Except as specifically modified in this article, all other requirements of this Code for permanent wiring shall apply to temporary wir ing installations.
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sasorikage said:
I feel there needs to be a disconnect sized properly at the service since it exceeds the lengths on the tap rules.Thanks again.
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Does your equipment comply with 240.21(B)(5) which allows unlimited tap lengths for some outdoor installations?
 
First, I want to endorse Don's answer.

Your description (and location) sounds vaguely like a mining installation which is generally exempt from the NEC. Conversely, many experienced mining electricians are under the false impression that what they did in the mines is acceptable anywhere and I have seen such applications attempted in several industrial facilities.
 
sasorikage said:
Hello, I have a question in regards to the tap rules. I can not find anything that exempts the tap rules in a temporary installation. Is this correct? Or are there exceptions that I am not aware of. Any help is greatly appreciated. The installation is feeding multi equipment in the field from a service disconnect the distance to the equipment is over 80 feet. Their current installation is a gutter on the power skid from which they tap to conductors sized to the various equipment loads. I feel there needs to be a disconnect sized properly at the service since it exceeds the lengths on the tap rules.Thanks again.
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Is this inside or outside?
 
jim dungar said:
Does your equipment comply with 240.21(B)(5) which allows unlimited tap lengths for some outdoor installations?
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rbalex said:
First, I want to endorse Don's answer.

Your description (and location) sounds vaguely like a mining installation which is generally exempt from the NEC. Conversely, many experienced mining electricians are under the false impression that what they did in the mines is acceptable anywhere and I have seen such applications attempted in several industrial facilities.
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I just wanted to add that tap rules are a bit different for Supervised Industrial Installations. See 240.92
 
Two problems I see is 240.21 is for feeder taps not taps to various loads without any OCPD at the loads, 210.19 is for branch circuit taps and the type of loads mentioned does not fit any of these descriptions

Second is the EGC's protecting these loads are sized for the normal sized circuit OCPD for a load, in some cases they will be undersized such as a #10 for a 60 amp OCPD, if the tap is to a 10x supply then these EGC's can easlly be damage to the point they could blow open without opening any OCPD, this could lead to the load becomming live and a direct shock hazard waiting for someone to touch.

Option is to install a small panel on the skid with a main breaker for the rating of the panel, and then protect the loads properly?
 
hurk27 said:
Again the OP does not mention any OCPDs at the skid for each of the loads supplied, so 240.92 also only addresses feeder taps, which must land on a OCPD.
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My post wasn't in reply to the OP.

Regarding the OP, he did not state the pertinent ratings, but it sounds as the main to the skid is a feeder tap. OCP is required at one end or the other at the very least, as the current installation appears to have taps tapping a tap.
 
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Smart $ said:
My post wasn't in reply to the OP.

Regarding the OP, he did not state the pertinent ratings, but it sounds as the main to the skid is a feeder tap. OCP is required at one end or the other at the very least, as the current installation appears to have taps tapping a tap.
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If there is no OCPD's at the skid then there is no feeder, it becomes an uncontrolled current load that can easily overload this tap, so this makes it a branch circuit tap that doesn't meet the rules in 210.19

Ya I know but I was just picking up on how he wrote it, like you said, it sounds like taps tapping a tap without any OCPDs for the smaller loads, which is why I pointed out the danger of the small EGCs that could be damaged if a fault was to happen in these smaller loads.

Their current installation is a gutter on the power skid from which they tap to conductors sized to the various equipment loads.
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Like I pointed out he needs a panel with a main breaker at the skid so they could protect these smaller conductors as well as protect the main tap conductors from being overloaded, fault protection for the main tap conductors is done via the 10x rule and the 10' limit.

This is like using this main tap to feed a bunch of receptacles at the skid, you have no way of controlling the load from over loading the main tap conductor, this is what I meant by uncontrolled tap which is not allowed by the NEC, which is why tapping a tap is not allowed.
 
Thank you very much for your replies. I was able to draft a plan for installation with your suggestions. I had a hard time explaining to the owners that just because the installation had worked in the past, it did not mean it was compliant.
 
sasorikage said:
Thank you very much for your replies. I was able to draft a plan for installation with your suggestions. I had a hard time explaining to the owners that just because the installation had worked in the past, it did not mean it was compliant.
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That seems to be a fairly common explanation that comes up often that doesn't always sink in to the owners.:(
 
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