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Supplemental and Obsolescence Digest 174

Obsolescent Circuit Breakers

Circuit Breakers for NQO, NQOB and NQOD Panelboards, Branch Circuit Breakers and Mounting Assemblies for ML Panelboards

 

Replacing Obsolescent Q1 and Q1B Circuit Breakers In NQO, NQOB and NQOD Panelboards

 

Q1 and Q1B circuit breakers have been replaced by QO and QOB circuit breakers.

Table 1 below is used for replacing 1P, 2P or 3P Q1 and Q1B circuit breakers with QO and QOB branch circuit breakers in NQO, NQOB and NQOD panelboards.

Table 2 below is used for replacing Q1 and Q1B main circuit breakers in NQO and NQOB panelboards.

 

Table 11.4:

Replacing Q1 and Q1B Circuit Breakers with QO and QOB Branch Circuit Breakers

Panelboard Type	Branch Circuit Breaker		Mounting Assembly Requiredc	$ Price
	Obsolete	Available
NQO	Q1	QO	SK5669a	62.00
NQOB	Q1B	QOB	SK5668	62.00
NQOD		QO	SKNQOD225b	50.00
NQOD		QOB	SKNQOD225b	50.00

 

Table 11.5:

Replacing Q1 and Q1B Main Circuit Breakers in NQO and NQOB Panelboards

Panelboard Type	Main Circuit Breaker		Mounting Assembly Requiredc	$ Price	Retaining Kit Requiredd	$ Price
	Obsolete	Available
NQO	Q1	QO	SK5669a	62.00	PK1MB	4.80
NQOB	Q1B	QOB	SK5668	62.00	—	—

a	Mounting assembly SK5669 is used to mount both Q1 and QO circuit breakers. Not required for replacement purposes.

b	225 A maximum. For 400-600 ampere circuit breaker mounting assembly, see Class 1630 Service Bulletin.

c	Discount Schedule PE1A.

d	Discount Schedule DE3A.

 

Branch Circuit Breakers and Mounting Assemblies for ML Panelboards

Replacement circuit breakers for ML panelboards are determined by the manufacture date of the panel and the panel depth. (See chart below)

 

 

Table 11.6:

Replacement Circuit Breakers in ML Panelboards

Manufacture Date	Panel Depth		Availability of Replacement Circuit Breakers
	in.	mm
1948–1956	8.63	219	No Replacements Available
1958–1961	10.00	254	No Replacements Available
1962–1968	10.63	270	Refer to Tables Below

 

The tables below are used for replacing or adding circuit breakers to 10-5/8 inch deep ML panelboards manufactured from 1962-1968 and for switchboards manufactured from 1962-–1968.

 

Table 11.7:

Replacement of Existing Circuit Breakers

Existing Circuit Breaker	Ampere Rating	Mounting Height		Cat. No. Prefix	Replacement Circuit Breaker	Mounting Assembly Required	Poles Required	Single or Twin (Mounting Assembly)	Mounting Assembly $ Price
		in.	mm
ML-1	15–100 A	4.50	114	989 or 999	FAL	SK4515e	3P	Twin	1091.00
ML-3	100–225 A	6.00	152	997	KAL	SK4516e	3P	Twin	1189.00
LA (W)	225–400	8.25	210	LA	LAL	SK4517	3P	Single	1423.00
MA (W)	125–1000 A	8.25	210	MA	MAL	SK4578	3P	Single	1855.00
FAL	15–100 A	4.50	114	FAL	FAL	No Mounting Assembly Required	3P	Twin	N/A
KAL	70–250 A	4.50	114	KAL	KAL		3P	Twin
LAL	125–400 A	6.00	152	LAL	LAL		3P	Single
MAL	300–1000 A	9.00	229	MAL	MAL		3P	Single
MAL	125–250 A	9.00	229	MAL	LAL	SK4517	3P	Single	1423.00

 

Table 11.8:

Adding New Circuit Breakers

Cat. No. Prefix	Ampere Rating	Mounting Assembly Required	Mounting Height		Poles Required	Single or Twin (Mounting Assembly)	Mounting Assembly $ Price
			in.	mm
FAL	15–100 A	SK4515	4.50	114	3P	Twin	1091.00
KAL	70–250 A	SK4516	4.50	114	3P	Twin	1189.00
LAL	125–400 A	SK4517	6.00	152	3P	Single	1423.00
MAL	300–1000 A	SK4578	9.00	229	3P	Single