Ac On/Off Circuit Breaker On Mx Series Front Panel; Table 3-1: Suggested Input Wiring Sizes For Each Mx Cabinet - Ametek California Instruments MX15 Series User Manual

The input power cables and protective circuit breaker used must be large enough to handle the
input current and input voltage of the power source and must conform to local electrical codes.
Consult a qualified electrician prior to installation. Table 3-1 shows the size of the cables that
may be used per MX15 cabinet. Note that wires must be sized to accommodate the worst-case
maximum current that may occur under low line conditions. Local electrical codes may also
require different wire types and sizes. These ratings should also be used when selecting a
circuit breaker or equivalent disconnect device.
Cable lengths must not exceed twenty-five (25) feet. For lengths greater than 25 feet, calculate
the voltage drop from the following formula:
2 X DISTANCE X CABLE RESISTANCE PER FT. X CURRENT = VOLT DROP
Nominal Line
Voltage
480 V
400 V
230 V
208 V
* Using high temperature rated wire. Always consult the National Electrical Code and/or local code
regulations for proper rating and size of wire cabling prior to installation.
CAUTION:

3.5 AC On/Off Circuit Breaker on MX Series front panel.

It is important to understand the purpose and operation of the On/Off circuit breaker of the MX15
located on the left side of the front panel. This is a 2A rated breaker that is used to engage and
protect the LV Power supply of the MX15 chassis only. The LV Power supply provides DC bias
power to the entire MX15 system. The AC input power is routed through a set of three AC line
fuses (F1, F2 and F3) located in the lower right bottom corner of the MX15. (See Figure 3-2 for
fuse locations). These fuses protect the MX amplifier and the AC input transformer from
excessive input currents. The AC input power is connected to the input transformer through a
large three-pole contactor. Removing AC power to the LV Power Supply by opening the front
panel circuit breaker (moving the lever to the down (OFF) position) will cause this contactor to
lose its coil voltage and will result in it opening and disconnecting the input transformer and
amplifier from AC mains input.
MX15 Series
Load Current Wire Gauge (US)
@ low line
25 A rms
30 A rms
52 A rms
58 A rms

Table 3-1: Suggested Input Wiring Sizes for each MX Cabinet *

Capacitors in the power source may hold a hazardous
electrical charge even if the power source has been
disconnected from the mains supply. Allow capacitors to
discharge to a safe voltage before touching exposed pins of
mains supply connectors.
Power modules need at least 15 Minutes to discharge to safe
levels before they can be removed.
Circular Mils
(Kcmils)
8 A W G 11.50
8A W G 11.50
8 A W G 18.00
6 A W G 26.24
Metric (mm2)
5.8
5.8
9.1
13.3
37