This document outlines procedures for checkout and commissioning of electrical equipment. It discusses checking the correct operation of safety devices, phasing of connections, and motor rotation. It also covers minimum requirements for ground system tests, including maximum resistance limits between the grounding grid and various grounding points. Finally, it specifies that insulation resistance tests shall be conducted prior to energizing equipment using an appropriate DC megger voltage.

1. Checkout and Commissioning of Electrical
Equipment
Dibi EPS Offsites
M:Engineering2311 DIBI Offsite3 - Engineering3.2 - Specifications2311-S5500
Checkout and Commissioning of Electrical Equipment2311-S5500, Rev. A2311-S5500
Checkout & Comm. of Elec. Equip, Rev. A.doc
11/04/05
Page 8 of 39
v. The correct operation of all shutdown safety devices, such as
limit switches, shall be checked.
w. The proper phasing of all connections and phase rotation of all
rotating machines shall be checked.
x. Motors shall be checked for proper rotation before coupling or
connecting to the load.
3.3.3 Ground System Tests
a. This section covers the minimum testing requirements for
grounding systems. The Contractor is responsible for the
adequate grounding of all equipment in accordance with NFPA
No. 70, National Electrical Code (NEC) and the Technical
Requirements.
b. The resistance between the grounding grid and the following
grounding points shall not exceed 1 ohm:
• Each point used to ground platform lightning protection
equipment.
• Each point used to ground electrical equipment enclosures.
• Each point used to ground wiring support systems such as
cable armor, conduits, and trays.
c. The resistance between the grounding grid and system neutrals
shall not exceed the following:
• 600-volt or less equipment - 1 ohm
• High-resistance ground system - 15 ohms
• Low-resistance ground systems - 1 ohm
3.3.4 Insulation Resistance Tests
a. Insulation resistance tests shall be conducted prior to energizing
the equipment.
b. A 500-volt DC megger shall be utilized for low-voltage
equipment (600 volts and below), and either 1000-volt or 5000-
volt DC megger shall be utilized for high-voltage equipment
(above 600 volts).
c. As applicable, Contractor shall measure and record resistances
of the following on the check sheets: