Siemens ep1333-1lb00

By Abdullah Zahid
12 min read
Siemens 6EP1333-1LB00 SITOP PSU100L 24V 5A DIN rail power supply for industrial automation control cabinets

Siemens 6EP1333-1LB00 SITOP PSU100L 24 V/5 A Stabilized Power Supply: Specs, Performance, and Selection Guide

Controls engineers specifying a 24 V DC rail for a mid-size automation cabinet frequently land on the Siemens 6EP1333-1LB00 — a compact, single-output SITOP PSU100L power supply rated at 5 A continuous output from a 100–240 V AC input. If you are confirming this is the correct model before committing to a build, the key facts are: 50 mm DIN rail width, 120 W output power, 86% efficiency at rated load, and an MTBF of 3,076,166 hours at 40°C. Phase-out has been announced, so availability planning matters as much as the technical selection.

If you have already confirmed this is the right part, check current pricing and availability for the 6EP1333-1LB00 at LeadTime.ca — ships worldwide.

Who Should Buy the 6EP1333-1LB00 — and Who Shouldn't

The Siemens 6EP1333-1LB00 is the right choice for engineers powering standard automation control circuits where the load does not exceed 5 A continuous and cabinet space is constrained. It is specifically the right fit when all of the following are true:

  • Your control circuit load sums to 5 A or less at the 24 V DC rail, with derating accounted for above 45°C ambient
  • Your facility AC supply is 120 V or 230 V — the front-panel selector switch accommodates both, but must be set correctly before power-up
  • Your enclosure can accommodate a 50 mm wide, 125 mm tall, 120 mm deep DIN rail mount device on a standard 35 mm EN 60715 rail
  • CE marking and UL approval satisfy your market compliance requirements — note this unit is NOT NEC Class 2 certified
  • Your project schedule accommodates a 5+ week manufacturer lead time, or you have confirmed distributor stock in advance

If your load exceeds 5 A, move to the 6EP1334-1LB00 (10 A variant). If your load is 3 A or less and cost is a constraint, the 6EP1332-1LB00 is the appropriate downgrade. For new designs requiring integrated diagnostics or remote monitoring, evaluate the SITOP PSU100U series before specifying this phase-out model.

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What the 6EP1333-1LB00 Actually Does in a Control System

The Siemens 6EP1333-1LB00 is a single-output, DIN rail mount AC-DC switching power supply that converts facility AC mains — either 120 V or 230 V, selected by a front-panel switch — into a regulated 24 V DC rail at up to 5 A continuous. It belongs to the SITOP PSU100L (Lite) series, which targets standard factory automation requirements where proven reliability and compact footprint matter more than advanced diagnostics or modular flexibility.

In practical terms, this unit is the power backbone for control circuits: it feeds 24 V to PLC I/O modules, proximity sensors, solenoid valve pilots, safety interlock relays, and small motor starters. It is not a UPS, not a battery charger, and does not include an integrated circuit breaker. It requires an upstream AC protection device — fuse or circuit breaker — as mandated by IEC and NEC standards. Output voltage is adjustable from 22.8 V to 26.4 V via an internal potentiometer, giving engineers a modest trim range without external components. Convection cooling eliminates fan noise and fan-failure risk in sealed cabinets.

The MTBF figure of 3,076,166 hours at 40°C is a meaningful proof point for reliability-conscious specifiers. At 86% efficiency at the rated 5 A load, the unit dissipates approximately 18 W as heat — a low thermal burden that reduces cabinet cooling requirements compared to less efficient alternatives in the same class.

Typical System Architecture for the SITOP PSU100L

The 6EP1333-1LB00 sits between the AC mains distribution panel and the 24 V DC load bus, converting and isolating the control voltage from the power distribution system. Galvanic isolation between input and output is built in, satisfying SELV requirements per EN 60950-1.

  • AC mains panel (120 V or 230 V) feeds through an upstream fuse or circuit breaker to the power supply input terminals (L, N, PE)
  • The 6EP1333-1LB00 converts and regulates to 24 V DC at its output screw terminals (+, -)
  • Output feeds a 24 V DC bus bar or terminal block distributing power to PLC I/O racks, sensor loops, and solenoid loads
  • Optional parallel configuration: a second 6EP1333-1LB00 with balancing diodes on both outputs feeds the same bus for N+1 redundancy
  • Downstream loads — SIMATIC S7-1200 or S7-1500 I/O modules, safety relays, valve pilots — draw from the regulated 24 V rail

Industries and Applications Where This Power Supply Fits

The 6EP1333-1LB00 appears most frequently in discrete manufacturing and packaging machinery cabinets where a single 24 V rail at 5 A covers the entire control circuit. Automotive assembly lines use it to power sensor arrays and solenoid manifolds on fixture stations. Food and beverage facilities specify it for hygienic conveyor controls where IP20 cabinet mounting is standard and convection cooling avoids condensation from fan-driven airflows.

Material handling systems — particularly those with SIMATIC S7-1200 controllers — use this unit as the primary power source for I/O modules and distributed sensor nodes. Safety circuit designers specify it for emergency stop and interlock power rails where CE marking and UL approval are hard requirements. It also sees frequent use as a like-for-like replacement in legacy SITOP Lite installations, where the footprint and terminal layout allow direct swap without cabinet rework.

Water and wastewater treatment panels use it to power instrument loops and valve actuators in smaller pump station cabinets. HVAC and building automation integrators specify it for variable air volume controllers and damper actuator panels where 120 W is more than sufficient for the load.

Application Typical Deployment
PLC control cabinet (SIMATIC S7-1200) Primary 24 V DC supply for CPU, I/O modules, and HMI panel power
Packaging machinery Sensor power and solenoid valve pilot supply on format change stations
Safety interlock circuits Dedicated 24 V rail for emergency stop, light curtain, and safety relay modules
Legacy SITOP Lite replacement Drop-in swap for older PSU100L units in existing control cabinets
Redundant supply configuration Two units in parallel with balancing diodes for critical process control uptime
Water/wastewater panel Instrument loop and valve actuator power in pump station control enclosures

Purchase-Decision Specifications and Variant Comparison

Parameter Value Notes
Input Voltage Range 93–264 V AC Selector switch for 120 V or 230 V nominal operation
Input Frequency 47–63 Hz Supports both 50 Hz and 60 Hz mains
Output Voltage 24 V DC (adjustable 22.8–26.4 V) Internal potentiometer trim
Output Current 5 A continuous Derated 2%/K above 45°C ambient
Output Power 120 W 24 V × 5 A
Efficiency at Rated Load 86% At 25°C ambient, 5 A load
Output Ripple 50 mV typical / 150 mV maximum Measured at rated load
MTBF at 40°C 3,076,166 hours Reliability metric per manufacturer data
Dimensions (W × H × D) 50 × 125 × 120 mm DIN rail snap-on, 35 mm EN 60715 rail
Operating Temperature 0°C to 60°C Full 5 A rated to 45°C; derating above

Full technical specifications are available on the product page at LeadTime.ca.

Model Output Current Output Power Key Difference When to Choose
6EP1332-1LB00 3 A 72 W Lower current, cost optimized Smaller control circuits, cost-sensitive projects with loads at 3 A or less
6EP1333-1LB00 5 A 120 W Standard mid-range, proven reliability Most general automation cabinets; the most common SITOP Lite selection
6EP1334-1LB00 10 A 240 W Higher current, doubled power Larger loads, parallel redundancy base units, or systems approaching 10 A demand
SITOP PSU100U 5 A 120 W Updated diagnostics, remote monitoring New designs requiring integrated visibility; preferred over phase-out 1LB00
SITOP PSU100M Modular Configurable Multi-output, advanced features Complex systems needing custom or multiple DC output rails

If your architecture requires exactly 5 A at 24 V DC on a 50 mm DIN rail footprint and CE plus UL certification covers your compliance needs, the 6EP1333-1LB00 remains a directly confirmed match — check current availability at LeadTime.ca.

Expert Verdict: Honest Assessment and Procurement Reality

The Siemens 6EP1333-1LB00 earns its place in thousands of installed automation cabinets because it does exactly what a 24 V 5 A power supply needs to do — deliver clean, regulated DC with minimal thermal overhead — and does it in one of the narrowest DIN rail footprints available in this power class. The 50 mm width is a genuine advantage in tight enclosures. An MTBF of 3,076,166 hours at 40°C is not a marketing figure; it reflects a product that has been through significant field validation. The 86% efficiency at rated load means roughly 18 W of heat dissipation, which is meaningful when cabinet thermal budgets are constrained. For controls engineers powering SIMATIC S7-1200 or S7-1500 I/O expansions, solenoid manifolds, or safety relay modules from a single 24 V rail, this unit is correctly sized and certified for the job.

The honest limits are equally important. Phase-out has been announced — this is not a product you should anchor a new platform design around. For new machine builds with a multi-year production horizon, the SITOP PSU100U delivers the same 5 A at 24 V with updated diagnostics and is the more defensible long-term specification. The 6EP1333-1LB00 also has no integrated circuit breaker, which surprises some buyers: you must provide upstream AC protection per your local electrical code, and that adds a component to your BOM and cabinet layout. If your load analysis puts you above 5 A under any reasonable growth scenario, do not try to stretch this unit — move to the 6EP1334-1LB00 at 10 A rather than relying on the parallel configuration, which requires careful balancing diode design to avoid cross-current issues.

On procurement: typical manufacturer lead time is 5+ weeks for new orders, which is the single biggest risk for project-driven buyers. Distributor stock levels vary. This is not a part you want to discover is unavailable two weeks before commissioning. If your project schedule is tight, confirming stock before finalizing your design BOM is not optional — it is the first procurement step. Volume pricing is available at quantity 5 and above through authorized distributors. If you are replacing multiple units across a facility or stocking spares for a production line, a quantity conversation is worth having. If this matches your system requirements, view current stock and pricing at LeadTime.ca.

For volume pricing or to confirm lead time before committing to a build, contact the LeadTime.ca team directly — we ship worldwide.

Wiring and Installation Overview

Installation of the 6EP1333-1LB00 follows standard industrial power supply practice. Engineers requiring complete wiring diagrams and commissioning procedures should refer to the Siemens SITOP PSU100L product manual available through siemens.com. The following covers the critical checks and configurations for a correct installation:

  • Set the front-panel selector switch to match your facility AC supply — 120 V or 230 V — before applying power; an incorrect setting is the most common commissioning error on this unit
  • Connect input terminals L (line), N (neutral), and PE (earth ground) using 0.5–2.5 mm² single-core or stranded wire; an upstream AC protection device — fuse or circuit breaker — is required and is not included with the unit
  • Connect output terminals + and − using 0.5–2.5 mm² wire; output voltage can be trimmed from 22.8 V to 26.4 V via the internal potentiometer using a small adjustment tool — verify under full load after adjustment
  • Snap the unit onto a standard 35 mm EN 60715 DIN rail; the 50 mm width allows space-efficient placement alongside circuit breakers and terminal blocks; ensure adequate cabinet ventilation for natural convection cooling — no forced airflow is required, but ambient temperature at the unit must remain within the 0°C to 60°C operating range
  • If paralleling two units for redundancy, install balancing diodes on each output before connecting to the common bus; do not parallel units without diodes, as current sharing imbalance can damage one or both supplies

What Engineers Get Wrong When Ordering This Part

Before finalizing your order for the Siemens 6EP1333-1LB00, work through this verbatim checklist drawn from the most common specification errors on this model:

  1. Verify output current rating: model 1LB00 provides 5 A maximum; confirm load does not exceed this (at 45°C ambient, derating applies 2%/K above 45°C)
  2. Confirm input voltage setting: check selector switch position matches facility supply (120 V or 230 V); incorrect setting may cause malfunction
  3. Check load voltage tolerance: verify control circuits accept 24 V +/-3% (22.8 to 26.4 V adjustable range); sensitive equipment may require tighter tolerance
  4. Confirm external protection: unit does NOT include integrated circuit breaker; upstream AC mains protection device required per local electrical code
  5. Verify parallel operation if needed: model supports parallel connection for redundancy; requires balancing diodes and careful current sharing design
  6. Check ambient temperature derating: at above 45°C, output current must be derated at 2%/K; ensure cabinet ventilation is adequate or load is reduced

If any item on this checklist creates uncertainty about whether the 6EP1333-1LB00 is the right specification, contact the LeadTime.ca team to confirm the correct variant before ordering.

Frequently Asked Questions

Does the Siemens 6EP1333-1LB00 include a circuit breaker or fuse?

No. The 6EP1333-1LB00 does not include an integrated circuit breaker on the AC input side. You must provide an upstream AC mains protection device — a fuse or circuit breaker — as required by IEC standards and local electrical codes including NEC. This is a hard requirement, not optional, and must be accounted for in your cabinet BOM and layout.

What is the output current derating above 45°C for the 6EP1333-1LB00?

Above 45°C ambient, the 6EP1333-1LB00 must be derated at 2% per kelvin. At 50°C, usable output current drops to approximately 4.5 A (90% of rated). At 60°C — the maximum specified operating temperature — output current is approximately 3.5 A (70% of rated). Cabinet designers should measure actual cabinet ambient temperature at the unit location, not just room ambient, when doing thermal derating calculations.

Can the 6EP1333-1LB00 be used in parallel for redundancy?

Yes, the model supports parallel connection for increased current capacity or N+1 redundancy. However, parallel operation requires balancing diodes on each unit's output before connecting to the common 24 V bus. Without diodes, current sharing imbalance between units can cause one supply to carry a disproportionate load or allow reverse current flow, potentially damaging both units. The diodes must be sized for worst-case unbalanced current conditions.

Is the Siemens 6EP1333-1LB00 being discontinued — should I still specify it?

A phase-out has been announced for the 6EP1333-1LB00. The product remains available through distribution, but supply will not be indefinite. For existing installations requiring like-for-like replacement, this unit is an appropriate choice and the footprint is compatible with legacy SITOP Lite cabinets. For new machine designs or platform builds with a multi-year horizon, the SITOP PSU100U — which provides equivalent 5 A at 24 V DC with updated diagnostics — is the more defensible long-term specification.

What is the typical lead time for the Siemens 6EP1333-1LB00 and how do I avoid delivery risk?

Typical manufacturer lead time is 5+ weeks for new production orders. Distributor stock levels vary and can be shorter, but are not guaranteed. The safest approach for project-driven procurement is to confirm available stock at your distributor of choice before finalizing the design BOM — not after purchase order release. If stock is unavailable, evaluate whether the 6EP1334-1LB00 (10 A) or SITOP PSU100U can be substituted to meet schedule.

What certifications does the 6EP1333-1LB00 carry for North American and international markets?

The 6EP1333-1LB00 carries CE marking for the European Union, UL approval under UL 60950-1 for North American markets, EAC approval for Russia, Belarus, and Kazakhstan, BIS certification for India, and a CB certificate available on request. It is also RoHS compliant. Note that this unit is NOT certified as NEC Class 2, which means external protection and grounding per NEC code are required for North American installations.

Why Order the 6EP1333-1LB00 From LeadTime.ca

  • LeadTime.ca ships worldwide — no geographic restriction on sourcing, regardless of project location
  • Specializes in sourcing industrial automation components with variable or extended manufacturer lead times, including phase-out models like the 6EP1333-1LB00
  • Volume pricing available — relevant for facilities stocking spares or integrators ordering across multiple machine builds
  • Direct contact with the team for lead time confirmation before committing to a design or purchase order

At-a-Glance Summary

  • Model: Siemens 6EP1333-1LB00 — SITOP PSU100L 24 V/5 A Stabilized Power Supply
  • Output: 24 V DC at 5 A continuous (120 W); adjustable 22.8–26.4 V via internal potentiometer
  • Input: 93–264 V AC with front-panel selector switch for 120 V or 230 V nominal operation
  • Efficiency: 86% at rated 5 A load and 25°C ambient
  • MTBF: 3,076,166 hours at 40°C
  • Dimensions: 50 mm wide × 125 mm tall × 120 mm deep; snap-on 35 mm EN 60715 DIN rail mount
  • Cooling: natural convection — no fan required
  • Derating: 2%/K above 45°C ambient; maximum operating temperature 60°C
  • Certifications: CE, UL (UL 60950-1), EAC, BIS, CB — NOT NEC Class 2 certified
  • External AC protection device required — not included with unit
  • Parallel redundancy supported — requires balancing diodes on outputs
  • Phase-out announced — confirm stock availability before committing to new designs; consider SITOP PSU100U for new platform builds
  • Typical lead time: 5+ weeks from manufacturer; distributor stock varies