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Siemens 3UG3042-1BP50 — Process / Temperature Controllers

Siemens 3UG3042-1BP50 SIRIUS Monitoring Relay, 3-Phase Volta

MPN3UG3042-1BP50

Siemens SIRIUS monitoring relay, 3UG3042-1BP50, 45 mm, 3-phase voltage + PEN conductor monitoring, under/over voltage, 2 changeover contacts, AC 3x400 V 50/60 Hz, screw connection, snap-on mounting, IP20.

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

3UG3042-1BP50 — Identification
ParameterValue
Product line / brand nameSIRIUS
3UG3042-1BP50 — Environmental
ParameterValue
Ingress protection (IP rating), wiredIP20
3UG3042-1BP50 — Mechanical
ParameterValue
Mounting typesnap-on mounting
3UG3042-1BP50 — Other specifications
ParameterValue
During operation-20 ... +50 °C
Reference code acc. to DIN EN 81346-2K
Number of poles for main current circuit3

Product details

The Siemens 3UG3042-1BP50 is a SIRIUS monitoring relay for three-phase mains — it watches all three phases plus the PEN (protective earth + neutral) conductor for under-voltage and over-voltage conditions, and switches its two changeover contacts when a fault is detected. Rated for 3 x 400 V AC at 50/60 Hz, this 45 mm-wide unit snaps onto a standard DIN rail (snap-on mounting per) and is IP20 finger-safe for panel installation. The operating temperature range of -20 to +50 °C covers most indoor control cabinets without derating.

The 3UG3042-1BP50 monitors three-phase voltage plus the PEN conductor — that PEN monitoring is the key differentiator versus a basic phase-loss relay. It detects not just phase imbalance or loss but also neutral displacement (common in IT or TN-C-S systems). The two changeover contacts (2 CO) give you one set for alarm and one for trip, or you can wire them in series for fail-safe.

Frequently asked questions

What is the closest functional second-source or replacement?

The official replacement named in the description is the Siemens 3UG4616-1CR20. That is the part to evaluate for a BOM update. The peer contactors listed (3RT1015-1BB42, 3RT1017-1AP01, 3RT2027-1AF00) are power contactors, not monitoring relays — they serve a different function and are not substitutes.

What is the mounting type for this relay?

Snap-on mounting onto a 35 mm standard DIN rail per DIN EN 50022. No screws needed for the rail attachment.

What is the IP rating and operating temperature range?

IP20 (finger-safe, no water protection) per. Operating temperature range is -20 to +50 °C during operation.

What compliance documentation is available for this part?

The evidence does not list specific certifications (UL, CSA, CE, RoHS, REACH) for this MPN. The reference code according to DIN EN 81346-2 is K, which is the standard classification for relay functions. For formal compliance documents, an RFQ should request the manufacturer's declaration.

MPN
3UG3042-1BP50