PANEL INSTALLATION

All connections to ACM20 power meters must be made after the unit

is securely attached to the panel and with all associated load and

supply voltages de energized (off), using extreme caution and observ-

ing all safety measures applicable to the user’s installation.

Care should be exercised when passing conductors through the

power meter’s built-in current transformer L1. The installed wire-

positions should be such that minimal mechanical forces are applied

to current transformer L1, TB1, or to the ACM20 power meter itself.

In high-vibration environments, it is strongly recommended that

adequate strain reliefs be used for all wiring.

Using Figure 5 as a guide, carefully insert the ACM20 assembly into

the panel opening. From the rear of the panel, install and then tighten

the four #2-56 hex nuts over the threaded studs. Tighten each nut to

15 to 20 ozf-in (0.106 to 0.140 N-m). Use only the factory-supplied

hardware as the use of substitute hardware could result in an unsafe

installation and/or adversely affect the reliability of the installation.

The recommended range of panel thickness that can be used with the

supplied hardware is 0.040 inches (1.0mm) to 0.25 inches (6.4mm).

Panel thicknesses outside of this range may require additional user-

supplied hardware or modifications. Front panel space permitting,

ACM20 power meters will fit most existing ACA-20RM / ACA-20PC

ammeter cutouts, allowing for easy upgrading of existing installations.

Figure 5. Panel Installation

SIDE VIEW

2-56 Hex Nuts (4 places)

Tighten each nut to 15 to 20 ozf-in (0.106 to 0.140 N-m).

L1

ACM20

PANEL

PANEL CUTOUT

RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS

INTERNAL CORNER RADII:

0.032 (0.81) MAX.

1.07

(27.18)

0.838* - 0.870

(21.29* - 22.10)

1.336* - 1.426

(33.93* - 36.22)

1.626 (41.30)

0.093 (2.362) DIAMETER (4 REQUIRED)

* The two dimensions marked with an * specify the

minimum recommended panel cutout opening for

ACM20 power meters. Space permitting, the larger

dimensions noted (0.87in., and 1.426in.) should be

used. The panel opening must be centered vertically

and horizontally between the four 0.093 (2.362mm)

diameter holes.

ACM20 Series

Four-Function AC Power Meters

www.murata-ps.com/dpm

email: sales@murata-ps.com

03 Mar 2011

MPM_ACM20 Series.A09 Page 5 of 6