6-5.3 Current Limiter Replacement (Mdsl); 6-5.3.1 Replacing Type Ma And Mb Current Limiters; 6-5.3.2 Replacing Type Md Current Limiters; 6-5.3.3 Replacing Type Md Current Limiters On Mdsl20 Breakers - Eaton MDN-408 Instructions For Installation, Operation And Maintenance

6-5.3 CURRENT LIMITER REPLACEMENT (MDSL)

NOTICE
Do not replace limiters with sizes other than permit-
ted by Table 3.8. MDSL current limiters have been
tested and approved by Underwriters Laboratories,
Inc. for use in MDSL circuit breakers when applied
according to Table 3.8. They are not electrically or
physically interchangeable with current limiting
fuses or any other design.
The current limiters are held in place in an extension
provided on the back of the circuit breaker (Figure 6-9).
They can only be removed from the circuit breaker and
replaced when the MDSL circuit breaker is removed
from its associated compartment.
6-5.3.1 REPLACING TYPE MA AND MB CURRENT
LIMITERS
The Type MA and MB current limiters have a single hole
in each end blade for attaching the limiters to the break-
ers. Removal of the limiters is easily accomplished by
simply removing the hardware.
Replacement of limiters should be performed as follows:
Note: Replace the center phase limiter first.
Step 1: Place the Belleville washer on the hex
head bolt such that the dome of the washer is
towards the head of the bolt.
Step 2: Place a flat washer on next.
Step 3: Place each of these hardware assem
blies through the holes in the limiter end blades,
and put one end through the center hole of the
breaker's fixed horizontal primary terminal. The
other end attaches to the center hole on the
rear stab.
Step 4: Place a lockwasher and a hex nut onto
each bolt and tighten by hand.
Step 5: The first bolt to torque is the one attach
ing the limiter to the breaker's fixed, horizontal,
primary terminal (torque to 40 ft-lbs).
Step 6: Torque the remaining bolt to 40 ft-lbs.

6-5.3.2 REPLACING TYPE MD CURRENT LIMITERS

Type MD current limiters have three holes in each of the
end blades for attaching the limiters to the breakers.
Removal of the limiters is easily accomplished by simply
removing the hardware.
I.B. 2C12060H08
Replacement of limiters should be performed as follows:
Note: Replace the center phase limiter first.
6-5.3.3 REPLACING TYPE MD CURRENT LIMITERS
ON MDSL20 BREAKERS
Replacement of MD limiters on the MDSL20 circuit
breaker is exactly the same as previously described in
Paragraph 6-5.3.2, except that the heat sinks (Figure 6-
9) must be installed with the bolt assemblies on each of
the breaker's fixed, horizontal, primary terminals.
Figure 6-9 MD Limiters Shown Mounted in Extension
For more information visit: www.EatonElectrical.com
Effective: May 2006
Step 1: Place the Belleville washer on the hex
head bolt such that the dome of the washer is
towards the head of the bolt.
Step 2: Place a flat washer on next.
Step 3: Place three of these hardware assem
blies through the holes in one of the limiter end
blades, and put this end blade on the breaker's
fixed horizontal primary terminal. These three
bolts can be threaded into the nut plate that was
originally installed and tighten by hand. The
other end of the limiter will attach to the rear
stab.
Step 4: Put the remaining three bolt assemblies
through the holes in the other end blades and
secure them with lockwashers and hex nuts.
Hand tighten only.
Step 5: First torque the bolts attaching the lim
iter to the breaker's fixed, horizontal, primary
terminal (torque to 40 ft-lbs).
Step 6: Torque the remaining bolts to 40 ft-lbs.
Step 7: Install the phase barriers between the
limiters.
Heat Sinks
Instruction Book
Page 66
Limiters