MCCB Cross-Reference: NY STM vs Schneider & ABB

Buyers regularly ask us the same question: “Which NY STM breaker replaces a Schneider NSX, an ABB Tmax, a CHINT NM1 or a Siemens 3VA?” This guide explains how professional cross-referencing actually works, what the STM series covers, and where to be careful.

1. Cross-Reference by Application Class, Not by Part Number

Breaker part numbers across brands do not map one-to-one. A correct cross-reference matches six engineering parameters:

1. Frame size (shell rating) — the physical current class of the breaker.
2. Rated current In — the trip unit setting you need.
3. Breaking capacity Icu / Ics — the short-circuit current the breaker can interrupt at your system voltage.
4. Number of poles — 1P to 4P.
5. Trip unit type — thermal-magnetic or electronic (LSI).
6. Mounting and connection — fixed, plug-in or withdrawable; front or rear terminals.

Match all six and the breaker will perform the same protection function. Miss one — usually Icu or trip type — and the substitution can fail a design review or a site inspection.

2. Class Comparison: NY STM vs Global Brands

The table below compares by application class, which is how engineers and procurement teams actually source.

Application class	NY STM series	Comparable global series
Thermal-magnetic MCCB, 125A-800A frames	STM6	Schneider NSX100-630, ABB Tmax XT2-XT4, CHINT NM1, Siemens 3VA1
Thermal-magnetic MCCB, 1250A-2000A frames	STM6 / STMRT-1250	Schneider NS1250, ABB Tmax XT5-XT7, CHINT NM1-1250, Siemens 3VA2
Electronic trip (LSI), adjustable	STM6E	Schneider NSX with Micrologic, ABB Tmax XT with Ekip, CHINT NM8
Residual-current protection (MCCB + RCD)	STM6L / STM6LE	Schneider NSX with Vigi module, ABB Tmax with RC units
DC protection for solar and storage	STM7DC	ABB Tmax PV, Schneider ComPacT NSX DC
Smart / IoT metering breakers	STM6ZY / STM6EY	ABB Ekip UP, Schneider PowerTag breakers

Within each class, STM product records describe thermal-magnetic or electronic trip options and related accessories such as shunt trips, undervoltage releases, alarm contacts and auxiliary contacts. Any standards or test-report claim must be checked against the exact replacement model.

3. What Cross-Reference Does NOT Guarantee

Honesty matters more than a quick sale, so here is what a class match does not give you:

• Mechanical interchangeability. Busbar positions, drilling patterns and terminal layouts differ between brands. A class-equivalent breaker is a functional replacement, not a drop-in part.
• Accessory compatibility. A Schneider rotary handle does not fit an STM6. Order the accessories of the brand you install.
• Selectivity coordination tables. Upstream-downstream discrimination tables are brand-specific and must come from the manufacturer’s test reports.

If your project requires formal substitution documentation, ask us to check the available model-specific documents and dimension drawings before purchase.

4. How to Send Us a Cross-Reference Request

Send us the nameplate data of the breaker you want to replace:

• Brand and model, e.g. “Schneider NSX250F TM200D 3P”
• In, Icu, poles and voltage
• Application (distribution, motor, solar)
• Annual quantity

We can compare the request with recorded options in the STM6 thermal-magnetic, STM6E electronic or STM7 new-energy high-voltage series. Any proposed substitute, document set, sample availability and lead time are fixed for the exact model in the quotation.

See also: MCCB Selection Guide: Frame Size, Breaking Capacity and Trip Curves and MCCB vs MCB.