Find the source for your panel.

Quick answer

Eaton's catalog defines two kinds of breaker: "Specified breakers are listed by the manufacturer of the panelboard for use in a particular panel", and Classified breakers are "for use in place of the breakers specified on the panelboard" [E2 p.V1-T1-101]. UL ties a Classified breaker to the panelboards named on the compatibility list supplied with it [U1 items 97–99]. UL limits Classified breakers to systems of 120/240 V and 10 kA available short-circuit current or less [U1 item 97]. Eaton states its Classified breakers can be used "in applications up to and including 120/240 volts, 225 ampere (A) panels" [E4 p.2].

How to use this chart

1. Find the brand, the catalog number and the breaker types on your panel label. See How to read your panel label (diagram D1).
2. Find your panel brand in the chart. Each row quotes or lists what the cited document prints, with its source ID and page.
3. Open the cited document and page. If the chart and your label disagree, the label wins.

1. 01

   Record the label

   Keep the complete panel identifier, breaker-type list, date and ratings together. Q7

2. 02

   Read the exact document

   Keep the maker, document revision and original page with the record. E1

3. 03

   Retain conditions and conflicts

   Record the printed limits and the panel maker’s separate statement. Q1

4. 04

   Bring the references to an electrician

   A document search does not decide what may be installed. S10

Original drawing and source annotations

The original drawing is schematic, not a product label, field measurement or installation instruction.

Open the original full-size SVG

The panel label and the electrician / authority having jurisdiction decide.

Sources: Q7 Square D 1100CT0501 pp.33-34, 60; S10 Murray 4810366 Rev. D p.1; S1 Siemens letter 2019-09-05 pp.1-2 (copy linked from the Siemens Sandy FAQ); E1 Eaton IL00304001Y p.1;

S4 Siemens QD brochure p.2; Q1 Square D FAQ FA109246; Q4 Square D 0700DB2001; C3, C7, C8, C10 CPSC notices. This chart lists documents to read; it is not installation guidance.

The chart

Each row cites the source ID and page; full titles are in the source list at the bottom.

What the documents disagree on

• Does a Classified breaker void a Square D panel's listing or warranty?
  • Square D says QO and Homeline load centers are listed to accept only Square D breakers, and that other manufacturers' breakers void the UL listing and warranty [Q1].
  • Its residential warranty: "Schneider Electric disclaims all liability for damage, injury or non-performance caused by the use or failure of incompatible or UL® classified circuit breakers." [Q4 p.1]
  • Eaton says its Classified breakers comply with NEC 110.3(B) and are UL listed for specific loadcenters [E4 p.1].
  • We show both positions and do not decide between them. Ask Square D about the warranty, and your AHJ about code compliance.
• Eaton's own naming changes between editions.
  • GE breakers are written "THQ" in an older Eaton chart (file metadata 2011) [E0] and "THQL" in the 2024 list and 2026 brochure [E1 p.4] [E3 p.3].
  • Eaton's QO-replacement line appears as CHQ in the catalog [E2 p.V1-T1-102] and as CHFQ in the 2026 brochure [E3 p.3].
  • We quote each document's catalog numbers exactly as printed.
• Third-party "Classified" wording. Connecticut Electric's catalog describes its UBI breakers as "Safety Agency Certified to UL489" [CE1 PDF p.2]. UL's public Product iQ search for the Classified category DIXF, run on 2026-11-15, returned five entries: four Eaton files and one Siemens file [P1]. Separately, CPSC records that Connecticut Electric, acting as a distributor, recalled about 64,000 counterfeit "Square D" QO and QOB breakers in 2007 [C14].

Era cut-offs that change the answer

Recalls to check first

Federal Pacific Stab-Lok: in 1983 CPSC "closed the matter without making a determination as to the safety of FPE circuit breakers" [C1].

Common confusions

• "Eaton BR fits, so it's fine in my Siemens/Murray panel."
  • Eaton's classified line for other makers' panels is Type CL, not BR [E2 p.V1-T1-103] [E1].
  • Eaton describes BR as the replacement for Westinghouse, Challenger and Bryant loadcenters [E5 PDF p.5].
  • Eaton's knowledge base: BR is "Not UL listed but 'fits'" in American Switch, Arrow-Hart, General Switch and GTE/Sylvania loadcenters [K5].
• "Eaton CL is just a BR for any panel." Eaton says CL is not UL listed for its own BR loadcenters [K3].
• "Same amp rating means compatible." UL's compatibility list ties a Classified breaker to specific panel catalog numbers and supply limits [U1 item 99].
• "Any Murray panel takes Siemens."
  • Siemens' letter names Murray Meter Combo, EQ Small Circuit and Rock Solid load centers "manufactured after January 2002" [S1 p.1].
  • For products made before that date it says to "refer to the wiring diagram affixed to the inside of the door of the loadcenter" [S1 p.1].

FAQ

Questions taken from search-engine question data (Google autocomplete and "People also ask" boxes) recorded on 2026-11-15 for eight target queries (raw/serp/paa_2026-11-15.txt). We answer a question only where a manufacturer, UL or CPSC document covers it.

Does the breaker brand have to match the panel brand?
Eaton's catalog describes two routes: specified breakers, which "are listed by the manufacturer of the panelboard for use in a particular panel", and Classified breakers "for use in place of the breakers specified on the panelboard" [E2 p.V1-T1-101]. UL ties a Classified breaker to the panelboards on its compatibility list [U1 items 97–99]. Square D states that non-Square D breakers void its load centers' listing and warranty [Q1].

What is a compatibility list?
UL describes it as a publication supplied with a Classified breaker. It lists the breaker's catalog numbers and ratings, the listed panelboards it may be used in, the breakers it replaces, and the maximum voltage and available short-circuit current [U1 item 99].

Are Classified breakers allowed in 200 A or 400 A panels?
Eaton states its Classified breakers can be used "in applications up to and including 120/240 volts, 225 ampere (A) panels" [E4 p.2].

What do CTL and Non-CTL mean?
Eaton's catalog: "Paragraph 384.15 requires branch circuit panelboards to be provided with physical means to prevent the installation of more overcurrent devices than that number of which the enclosure was designed, rated and approved. Class CTL Duplex, Quadplex and twin breakers (identified by a catalog number prefix BD, BQ, BQC and CHT) are equipped with a UL listed rejection tab over the line terminal. All OEM interiors have appropriately notched stabs to accept these rejection tab Class CTL breakers. Duplex, Quadplex and twin breakers manufactured without the rejection tab (identified by a catalog number prefix BR, BRD and CHT) are available for replacement purposes in older interiors." [E12 p.V1-T1-91] Siemens' and Murray's catalogs footnote certain duplex breakers "Non-CTL. For replacement use only in panels manufactured before 1968" [S6 PDF p.37, p.58].

Where do I find my panel's catalog number?
CPSC's 2010 Siemens recall release says: "The catalog number for the load centers and meter combos is printed on a label inside the metal box door and on the packaging" [C3]. Murray's instruction sheet likewise points to the wiring diagram label inside the door or cover for product ratings and acceptable components [S10 p.1].

What brand breakers are compatible with Square D?
The makers disagree, so both sides are shown. Square D says its QO and Homeline load centers are UL tested, listed and labeled to accept only Square D breakers, and that other makers' breakers void the UL listing and warranty [Q1]. Eaton prints "Type CHQ Replacement Breakers for Square D Type QO Loadcenters" [E2 p.V1-T1-102], and Siemens describes Type QD as UL Classified for specific Square D load centers [S6 PDF p.39] [S9 p.47].

Are Eaton, Westinghouse, Square D and Cutler-Hammer breakers compatible?
Eaton says its BR breakers are UL approved for Westinghouse, Challenger, Bryant, Cutler-Hammer and Eaton BR loadcenters [K6]. For Square D, Eaton prints "Type CHQ Replacement Breakers for Square D Type QO Loadcenters" [E2 p.V1-T1-102], while Square D says only Square D breakers keep its QO and Homeline listing [Q1]. Eaton's ¾-inch CH is only for CH loadcenters [E5 PDF p.5].

Will Eaton BR breakers fit a Square D panel?
Eaton: "BR breakers are UL approved to be used in the following loadcenters: Westinghouse, Challenger, Bryant, Cutler-Hammer, and Eaton BR loadcenters." [K6] Square D: its QO and Homeline load centers are "UL tested, listed, and labeled to accept ONLY Square D circuit breakers" [Q1].

Sources

All documents fetched 2026-11-15 or 2026-11-16 and archived with SHA256 (see SOURCE-LIBRARY.csv). Kind: primary = issued by the manufacturer/agency; primary-mirror = manufacturer document hosted by a third party.

Related reference photographs