Questionable Grounding or Code Compliant Installation?

[ken44]

I have a 4160 volt chiller starter cabinet that was recently worked on by contractors. They decided to ground the cabinet to a large water pipe some 50' away and the water pipe is not near the building entrance. We are concerned that this is a safety violation but an electrical engineer says that its okay. Input please!

 

[ron]

So they just bonded the cabinet to the pipe?

They didn't connect it to an ungrounded or grounded (neutral) conductor somehwere, did they? If so, no harm, no foul, I'm just not sure why they would have done it.

Is there an equipment ground with the feeder to the starter?

 

[petersonra]

It is unlikely to harm anything to do so, but I don't see that it is actually necessary, or especially useful.

The above presumes that a proper EGC was run.

 

[Dennis Alwon]

It is unclear if there is an egc. If there is then I say compliant otherwise I say it is not based on 300.3(B). I am assuming the conduit is metallic then no issue.

There is a section in 250.190 that is new to 2011. This is for over 1kv

(B) Grounding Electrode Conductor. If a grounding electrode conductor connects non–current-carrying metal parts to ground, the grounding electrode conductor shall be sized in accordance with Table 250.66, based on the size of the largest ungrounded service, feeder, or branch-circuit conductors supplying the equipment. The grounding electrode conductor shall not be smaller than 6 AWG copper or 4 AWG aluminum.
(C) Equipment Grounding Conductor. Equipment grounding conductors shall comply with 250.190(C)(1) through (C)(3).
(1) General. Equipment grounding conductors that are not an integral part of a cable assembly shall not be smaller than 6 AWG copper or 4 AWG aluminum.
(2) Shielded Cables. The metallic insulation shield encircling the current carrying conductors shall be permitted to be used as an equipment grounding conductor, if it is rated for clearing time of ground fault current protective device operation without damaging the metallic shield. The metallic tape insulation shield and drain wire insulation shield shall not be used as an equipment grounding conductor for solidly grounded systems.
(3) Sizing. Equipment grounding conductors shall be sized in accordance with Table 250.122 based on the current rating of the fuse or the overcurrent setting of the protective relay.