Air Products Gasguard 250, Руководство по установке

Страница: 33 / 68

Section 4: Electrical Connections
Revision E: July 1998 Page 4 - 3
After grounding the overall resistance must be measured. This resistance for the
equipment ground to the grounding electrode can not exceed one ohm (1
Ω
).
Check the effectiveness of grounding by attaching a wire to the nearest grounding
electrode and connect an ohmmeter in between the reference ground wire and the
enclosure.
4.2 Power Supply Connection
4.2.1 Gasguard 250 Controller
Each valve manifold box should be installed with an independent external circuit
interrupting device to remove power from the unit when maintenance on the
controller is required and should be Lockout/Tagout capable. This device should
be rated as a minimum at 240 volts, 3 amps, 50/60 Hz and 10,000 rms symmetrical
ampere interrupting capacity. The device should be accessible to the operators,
marked as the disconnecting device for the valve manifold box, and must have the
on/off position clearly marked for the operator.
A 1-1/8" diameter hole for 3/4" conduit is supplied for connecting the 120/240
VAC power supply to the GASGUARD™ 250 Controller. The conduit hole is
located on the top of the controller enclosure. See Figure 4.2 below.
Figure 4.2: View of Top of Gasguard 250 Controller