• 250 Ampere current source
• 4 current-source outputs (i.e., 5 A @ 120 Vac, 25 A @ 24 Vac, 120 A @ 6 Vac, 250 A @ 3 Vac)
• 4-line by 20-character LCD display
• Provides external current input (0-10 A)

The Vanguard MCCB-250 is a programmable, high-current source designed specifically for testing molded-case circuit breakers, thermal magnetic and solid-state overload motor-protection relays.

Built-in Timer

The MCCB-250’s built-in timer can test the

time-delay characteristics of protection relays

and molded-case circuit breakers. Once

the test is initiated, the current source and the

timer are automatically turned on at the next

zero-crossing point of the AC. The timer stops

when the MCCB-250 input detects a change

in the dry contact or voltage input, or detects

the removal of the test current. The test results

are then displayed in milliseconds and

fractions of cycle(s) on the unit’s back-lit LCD

screen (20 characters by 4 lines).

Current Source

The MCCB-250 has 4 current-source outputs

(5 A @ 120 Vac, 25 A @ 24 Vac, 120 A @ 6

Vac, 250 A @ 3 Vac) that conduct the test

current through the high-impedance load circuits.

Each current source can tolerate shortduration

over-loads up to 4 times the rated

current (1000 A max). This feature is used

for testing the instantaneous trip element of

molded-case circuit breakers. When using

this feature, the selected test current is displayed

on the LCD screen. When the MCCB-

250 is used as a current source, the currentfl

ow time (the current-on period) is displayed

External Current Input on the LCD screen.

The MCCB-250 also provides an external current

input (0 – 10 A). Both internal and external

current source readings can be viewed at

the same time.

Part number MCCB-250 MCCB-250 and cables

Part number MCCB-250-CASE MCCB-250 shipping case

Part number MCCB-250-10FT MCCB-250 test leads - 10 foot

Part number MCCB-250-20FT MCCB-250 test leads - 20 foot