Siemens MP390 Molded Case Circuit Breaker
- 90A
- 3 Pole
- Plug-On
Quantity
Siemens MP390 - 90A 3 Pole Molded Case Circuit Breaker
New
Quantity
Description
Part of the legacy Murray product line, this 90-amp, three-pole breaker delivers reliable thermal-magnetic protection for commercial and industrial electrical systems. It mounts into compatible Murray or Siemens load centers, providing a seamless fit for existing panelboards. Featuring a 10kA interrupting capacity at 240VAC, the unit includes common trip functionality and carries an HACR rating for heating and cooling equipment. Note that this model is officially replaced by the Siemens Q390.Specifications
| Brand | Siemens |
|---|---|
| Part Number | MP390 |
| Series | MP |
| Amperage | 90A |
| Poles | 3 |
| Mounting Style | Plug-On |
| Voltage | 240VAC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC |
| Frame Type | MP |
|---|---|
| Terminal Type | Lugs |
| For Use With | Murray Load Centers, Siemens Load Centers |
| Wire Gauge | 2-1/0 AWG (Cu/Al) |
| Max Wire | 1/0 AWG |
| Min Wire | 2 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Padlock Attachment |
|---|---|
| Standards | HACR, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Common Trip |
Product FAQs
5 answersWhat is the active Siemens cross-reference for the MP390?
Siemens phased out the Murray brand in 2019. The direct, manufacturer-approved replacement for the MP390 is the Siemens Q390.
Can Siemens QP breakers be used to replace Murray MP breakers?
Yes. Siemens issued a formal substitution letter confirming that Siemens QP breakers are UL-listed for use in Murray load centers manufactured after January 2002.
Is the MP390 HACR rated?
Yes, this breaker carries an HACR rating, certifying it for use with heating, air conditioning, and refrigeration equipment.
Can the MP390 be used in single-phase applications?
No. As a 3-pole breaker, it is designed exclusively for 3-phase systems and requires a 3-phase load center to engage all three bus bars.
What is the physical width of the MP390?
The breaker is 3 inches wide, occupying three standard 1-inch spaces in the panel.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 4 reviews.
- JVJulie V.Verified BuyerReviewingSiemens / Murray MP2100 - 100A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars3/5/26on breaker
so far so good on the refurbished breaker
- JFJon F.ReviewingSiemens / Murray MP250 - 50A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars12/17/20Sales
Fantastic group to work with...
- DSDavid S.ReviewingSiemens / Murray MP2100 - 100A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars1/5/20Thank you so much for
Thank you so much for sending me a 100 amp breaker that was in the condition that you said it would be in.With out your breaker I would still be in the dark Thank you David
- RARichard A.ReviewingSiemens / Murray MP2100 - 100A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/13/19Awesome!
Your prices and number of available items to choose from is Awesome!