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#10943 06/23/02 04:54 PM
Joined: Aug 2001
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pauluk Offline OP
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I don't recall this being discussed before.

Does the NEC specify what tests must be carried out upon completion of a new installation? Or is there a generally accepted series of tests that are performed?

I'm assuming that you would as a minimum do a megger test on the final system, but what about ground rod testing, verification of correct polarity, and so on?

#10944 06/23/02 05:38 PM
Joined: May 2002
Posts: 1,716
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Paul,in addition to checking overall installation and compliance to other ares of the code, most inspectors will check polarity with a receptacle analizer, check grounding with an ohmmeter, and require Fire alarm certification at the final inspection.

Most insulation and ground test are specified in the engineers specifications, although I have had inspectors who requested ground readings at the GEC. (ground megger)

The kicker to this is, per the NEC, if you can not achieve a value of 25 ohms or less on a ground rod you must add a second rod and that is all that is required whether this gets the 25 ohm minimum or not.


In medical installations certifications of equalpotential grounding, Isolation systems commissioning, Fire alarm certification, Generator commissionig, Critical, and Life safety branches to name a few are required.

This in the areas I work, some others may have other standards.

Roger

#10945 06/23/02 06:47 PM
Joined: Oct 2000
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Paul, this is all i've found......

Art 550, Mobile Homes, Manufactured Homes, and Mobile Home Parks.
550.17 Testing.

(A) Dielectric Strength Test. The wiring of each mobile home shall be subjected to a 1-minute, 900-volt, dielectric strength test (with all switches closed) between live parts (including neutral) and the mobile home ground. Alternatively, the test shall be permitted to be performed at 1080 volts for 1 second. This test shall be performed after branch circuits are complete and after luminaires (fixtures) or appliances are installed.

Exception: Listed luminaires (fixtures) or appliances shall not be required to withstand the dielectric strength test.


(B) Continuity and Operational Tests and Polarity Checks. Each mobile home shall be subjected to all of the following:
(1) An electrical continuity test to ensure that all exposed electrically conductive parts are properly bonded
(2) An electrical operational test to demonstrate that all equipment, except water heaters and electric furnaces, is connected and in working order
(3) Electrical polarity checks of permanently wired equipment and receptacle outlets to determine that connections have been properly made

#10946 06/24/02 12:21 PM
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pauluk Offline OP
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Thanks.

Our "regs." specify tests for correct polarity at outlets, switches in "hot" conductor, ground continuity, and so on.

Interesting on the mobile-home megger tests. For 1-ph 240V and 3-ph 240/415V our standard insulation test is at 500V DC (between every possible combination of phases & neutral, and between all phases+neutral strapped together and ground).
Absolute minimum allowable result is 0.5 Meg, although the IEE recommends that anything under 1 Meg be investigated further.

I should have also mentioned several tests specific to our ring circuits (Uh-oh! Not those again!).


[This message has been edited by pauluk (edited 06-24-2002).]


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