Branch Switch Replacement

Class 4620

Guidelines

STEP 1: Determine the panelboard interior type. If the date of manufacture is not known, compare your switch with the pictures below to determine the mounting rail direction. Only mounting rails that face outward will accept the Series D2 switch and its required mounting rail extension bracket.

STEP 2: Order a replacement switch from 30–200 A Obsolescent Switch Units—Series D2.

Panelboard Interiors

Illustration No.

Interior Catalog No. Prefix

Designed For Switch Type

Switch Availability/Order Information

1

Type QM 
in 31-inch wide box
built before 1961.

Series 1-4
30–200 A Maximum

NOT AVAILABLE
Series D2 switches are not compatible replacements for this application.

2

Type QM
in 31-inch wide box
built after 1961
and before 1984.

Series 1-4
30–200 A Maximum

NOT AVAILABLE
Order Series D2 switch from 30–200 A Obsolescent Switch Units—Series D2.

Series D2
30–200 A Maximum

Order Series D2 switch from 30–200 A Obsolescent Switch Units—Series D2. (Many still stocked in DS.)

3

Type QW
in 38-inch wide box
built before 1984.

Series 1-4
30–200 A Maximum

NOT AVAILABLE
Order Series D2 switch and plug-on extension assembly from 30–200 A Obsolescent Switch Units—Series D2.

Series 1-4
400–600 A

NOT AVAILABLE
QMB3400LA available order only from Lexington.

Series D2
30–200 A Maximum

Order Series D2 switch and plug-on extension assembly from 30–200 A Obsolescent Switch Units—Series D2.

4

Type QMB
in 35-inch or 38-inch wide box
built after 1984.

Series E1 or E2
30–800 A

Order from Digest Section 9.

 

Type QM (31-inch Wide)
Manufactured Before 1961

 

Type QM (31-inch Wide)
Manufactured After 1961 But Before October 1984

Panelboards manufactured before 1961 have the interior mounting rails facing inward (toward the bus). Switches and circuit breakers that fit in this interior type are obsolete.

 

Panelboards manufactured after 1961 have the interior mounting rails facing outward (away from the bus). This interior accepts Series 1-4 switches and Series D2 switches (shown above with required rail extensions). Order the Series D2 switch (includes mounting rail extensions) from 30–200 A Obsolescent Switch Units—Series D2.

 

Type QW (38-inch Wide)
Manufactured Before 1984

 

Type QMB
Manufactured After October 1984

Type QW panelboards were built to accept bolt-on 400 A and 600 A Series 1-4 switches. 30-200 A Series D2 switches may be installed as shown using the plug-on extension assembly from 30–200 A Obsolescent Switch Units—Series D2.

 

Series E1 panelboards will accept only Series E1 or E2 switches. Order from Digest Section 9.

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