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hec64 (Electrical) (OP)
14 Jul 10 21:29
We have a discussion on how to tag high voltage conduit.

We are doing a new installation of conduit for 4160 volts. We are putting several manholes and one of our engineers, who is doing the design, is assigning conduit tags from manhole to manhole and all the conduit tags are different for one service.

I told him this is unsafe since the electrician may go to the switchgear and said: this is conduit number 1006 and at the other end he wants to find conduit 1006. But he is going to find that the conduit 1006 has changed to conduit 1010.

My boss told me not to "critize" other people design since this is "bidable" and it is not important.

I told them that this is a safety issue and not if this is "bidable" or not.

Can someone tell me if there is an OSHA requirement on this or a California code requirement on this?

I have try to find it with no success.



 
davidbeach (Electrical)
15 Jul 10 0:00
A conduit can't change numbers.  If that can happen, there's not much point to providing numbers.  It is either conduit 1006 or it is conduit 1010, but there is no way that one conduit can be both.  Time to polish the resume and find somewhere else to work, that boss is bad news.
jghrist (Electrical)
15 Jul 10 8:54
I assume that you're talking about multiple conduit runs between panels, with manholes in between.  Say Conduit 1006 goes from Panel A to MH-1, Conduit 1007 from MH-1 to MH-2, Conduit 1008 from MH-2 to MH-3, Conduit 1009 from MH-3 to MH-4, Conduit 1010 from MH-4 to Panel B.  I see nothing wrong with this as long as there is a conduit plan showing where things are and a cable schedule showing what conduits the cable goes through.

If you numbered all the conduits the same, then it is difficult to refer to a single one.  This might be OK as long as you only had one conduit between manholes, but if you had multiple conduits it would be restrictive.
davidbeach (Electrical)
15 Jul 10 9:42
I don't see a problem with what jghrist describes.  I read the question as being that one end of a conduit was numbered 1006 and the next place that the conduit was accessible it was numbered 1010.
hec64 (Electrical) (OP)
15 Jul 10 11:10
David:

I want to apologize for the misunderstanding. It is as Jghrist is describing.  The conduit tag is the same between manholes, but changes when it leave the manhole or does not have any tag in the manholes.The problem arises on the fact that previous contracts the engineers used one conduit tag for the whole conduit run from switchgear 1 to switchgear 2 even though there are several manholes in between. So there has been already four or five consultants that have done the project and follow that rule. But during the installation, we discovered that the contractor may have made some mistake and found different tags at the end of the switchgear.

Instead of correcting it, the engineer decided to continue with the way the contractor has installed the conduit tags, except that there is no tags in the manhole, only at the end of each switchgear.  And there is no drawing indicating which conduit is which in the manholes. So in my opinion it will be easy to have the same tag at both side of the siwtchgear, even though it goes through several manholes.

But apparently this is not a safety problem or an OSHA issue, isn't it?.

That is the question.


 
jghrist (Electrical)
15 Jul 10 17:17
The lack of a drawing is the problem.  If you have more than one conduit between manholes, using the same conduit tag for the entire circuit would be very inflexible.  It would restrict conduit use based on the numbering system.
 
zaza123 (Electrical)
17 Jul 10 6:07
In my opinion there should be a similarity in the drawings & the actual at the site.
Now that you mention that many contractors & designers worked for the project, there must have been lot of confusion in the Tagging system.
 If the problem is only that of tagging you can keep the same Tag no. for the conduit from the starting to the end, but in the manhoples where that conduit is accessible you need to put the same Tag no. In case of multiple conduits if you dont Tag in the manholes you will find difficulty later in identifying the cables.

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