Description

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Product Overview

The neutral busbar 2x25 5pole is a 50 mm² distribution bar that gives five circuits one common neutral or protective earth point inside a control cabinet. Each of the five poles takes two conductors up to 25 mm², so ten outgoing cores land on a single bar instead of being stacked along a terminal rail.

What decides whether a bar like this still performs after a few years is its surface. Untreated copper and brass react with the humidity and sulfides present in most cabinets: the face dulls, then darkens, and the film that forms conducts poorly. Contact resistance climbs, the joint runs warmer at the same load, and the cabinet builder hears about it from the end user. Electrolytic tin plating at 3–5 µm seals the bar against that reaction before it ever leaves the packing line.

The bar arrives ready to mount. Pole pitch is held at the standard 18 mm or 25 mm module spacing, the end holes take standard DIN rail brackets, and the conductor follows your panel specification - tin-plated brass CuZn37 or high-purity copper C11000. Pole counts from 3 to 12 and alternative hole patterns are produced to drawing, so the same part number family covers a whole cabinet range.

Technical Specifications

Values below are the standard configuration. Confirm each line against your panel drawing or BOM before release: the continuous current in particular is set by the bar cross-section and by how the bar is mounted and ventilated.

Parameter	Value
Busbar Cross-Section	2 mm × 25 mm (50 mm² effective)
Number of Poles	5
Conductor Entries Per Pole	2
Conductor Range	Up to 25 mm² per entry
Conductor Material	Tin-plated brass (CuZn37) or high-purity copper (C11000)
Surface Finish	Electrolytic tin plating, 3–5 µm standard (5–8 µm option)
Conductivity	≥ 56 MS/m (brass) / ≥ 58 MS/m (copper)
Anti-Oxidation	Tin plating provides long-term corrosion resistance in humid environments
Continuous Current Rating	Set by bar cross-section and mounting - this series publishes 200 A for the 75 mm² bar and 300 A for the 90 mm² bar in free air; the 50 mm² value is confirmed on request
Screw Specification	M4 / M5 (depending on pole configuration)
Hole Diameter	4.2 mm (M4) / 5.2 mm (M5)
Recommended Torque	2.5–3.5 N·m for the M5 screw (series figure); M4 value confirmed on request
Pole Center Distance	Standard 18 mm or 25 mm pitch (specify when ordering)
Mounting	Compatible with standard DIN rail brackets
Service Environment	Indoor and outdoor distribution panels; humid and coastal locations supported by the heavy-duty plating option
Customization	OEM / ODM supported per customer drawings
MOQ	Depends on configuration; trial orders negotiable
Quality Guarantee	12–24 months from shipment date
Manufacturing Standard	ISO 9001 quality management system
Packaging	Standard export packaging; cartons of 50 or 100 pieces for the standard bar
Delivery Ports	Ningbo Port / Shanghai Port
Quote Turnaround	Within 24 hours

Core Advantages

Four design decisions do most of the work on a bar that has to sit in a humid cabinet for a decade.

Tin Plating Instead Of Bare Copper

Electrolytic tin plating at 3–5 µm covers the bar surface, the edges and the contact faces. Copper and brass no longer meet the humidity and sulfides in the cabinet air, so the dull-to-black oxidation cycle that raises contact resistance never starts. The bar is still conductive - and still bright - at the end of its service life.

Two 25 mm² Entries On Every Pole

Each of the five poles accepts two conductors up to 25 mm². Feed-in and feed-out can share a pole, so a run can be looped without doubling the pole count. Ten terminations on one bar is what makes this format compact enough for small enclosures.

A 50 mm² Cross-Section On A 2 mm Profile

A 2 mm × 25 mm bar carries the summed neutral current of the circuits it serves with more copper in the section than a thin stamped profile has. It mounts flat against the back plate and stays stable on the standard 18 mm or 25 mm pitch.

Uniform Pitch, Uniform Clamp Pressure

Every pole carries its own clamping screw, so torque is set pole by pole rather than shared along a single rail. Spring lock washers resist loosening under vibration, and brass screws are available where galvanic corrosion between dissimilar metals is the larger risk.

Wire Cage Terminal vs Traditional Brass Terminal

This heading is kept so the section matches the rest of the site. On this product the termination is a screw clamp on a tin-plated bar, never a wire cage, so the comparison below is written around that interface.

Point Of Comparison	Tin-Plated Screw-Clamp Busbar (This Product)	Traditional Bare Brass Bar
Conductor interface	Screw clamp bearing on a flat, tin-plated face	Bare screw seating on an oxidised bar surface
Entries per pole	Two conductors up to 25 mm² each	Usually one conductor per pole
Surface in a humid cabinet	Tin plating keeps the face bright and conductive	Copper and brass darken; the film blocks the joint
Contact resistance over service life	Stable, no periodic cleaning routine	Creeps up as the oxide layer grows
Cross-section and load	2 mm × 25 mm machined bar, 50 mm² effective	Depends on the supplier; thin profiles heat up sooner
Assembly	Five poles on one bar at fixed 18 mm or 25 mm pitch	Discrete terminals wired pole by pole
Ordering	Standard 5-pole, plus OEM pole counts 3P–12P and hole patterns to drawing	Fixed configurations only

Professional Production Process

Five steps, with the plating and the hole positions checked on every batch.

Bar cutting and forming - copper or brass bar is cut to length and formed to the customer drawing.

Punching and drilling - pole holes, terminal holes and end mounting holes are positioned to the drawing within its stated tolerance.

Electrolytic tin plating - the formed bar is plated to 3–5 µm standard, or 5–8 µm where a heavier coating is specified.

Screw assembly - M4 or M5 screws are fitted pole by pole, each with an integrated spring lock washer.

Inspection - plating thickness, hole position, thread condition and a torque check on the assembled poles are recorded per batch.

Material & Surface Treatment Options

Two material decisions carry most of the cost, so they are worth settling before the order is placed.

Conductor Material: Brass CuZn37 Or Copper C11000

Tin-plated brass CuZn37 reaches ≥ 56 MS/m and is the usual choice for cabinet builders working to a budget. High-purity copper C11000 reaches ≥ 58 MS/m and holds a marginally lower resistance over the same cross-section. Both come with the same electrolytic tin finish, and both are available at 50 mm² in this 5-pole format.

Tin Plating Thickness: 3–5 µm Or 5–8 µm

Standard plating is 3–5 µm, which covers indoor distribution boards, control cabinets and ordinary panel interiors. Where the cabinet sits in a coastal plant, a tunnel or any atmosphere carrying sulfide or salt, the 5–8 µm option is specified; the difference is how long the coating lasts before the base metal is exposed.

Screw Material: Galvanised Steel Or Brass

Galvanised steel screws are the standard supply and give the highest clamping force. Brass screws are non-magnetic and match the bar metallurgically, which removes the dissimilar-metal couple behind galvanic corrosion in humid and coastal installations. Both are supplied with integrated spring lock washers.

Application Scenarios

Four cabinet types where a compact 5-pole neutral bar does the work of a row of discrete terminals.

Control Cabinets And Distribution Boards

Machine and process control cabinets where the neutrals of several single-phase loads have to be collected without widening the terminal rail. Five poles at standard module pitch sit alongside breakers and contactors in enclosures that have little spare depth.

Lighting And Small Circuit Distribution Panels

Lighting panels and sub-boards feeding a handful of outgoing ways, where each way returns on the same dedicated bar instead of sharing a breaker terminal. One bar replaces the individual neutral terminals the schedule would otherwise call for.

MCCB And RCD Distribution Panels

Panels built around MCCBs and RCDs, where neutral has to stay separated from earth and return to a single point. The same bar is supplied in brass or copper for the protective earth role, so a cabinet can use one part number for both duties.

Photovoltaic AC Combiner Boxes

AC combiner boxes on PV arrays, where the inverter output neutral returns through an enclosure that sees wide temperature swings and, on coastal sites, a salt-laden atmosphere. The heavy-duty plating option is specified for those locations.

Frequently Asked Questions

Q: What is the difference between this bar and a plain copper busbar?

A: The bar is the same idea - one conductor shared by several circuits. The difference is the surface. Electrolytic tin plating at 3–5 µm prevents the oxidation that dulls bare copper and brass in humid cabinets and pushes contact resistance upward over time.

Q: How much current can the 2×25 5-pole bar carry?

A: Continuous current depends on the bar cross-section and on how the bar is mounted. This series publishes 200 A for the 75 mm² bar and 300 A for the 90 mm² bar in free air; the figure for this 50 mm² bar is confirmed on request against your load schedule.

Q: Which conductors fit, and how many per pole?

A: Each of the five poles takes two copper conductors up to 25 mm² - ten terminations on one bar. Hole diameter follows the screw size, 4.2 mm for M4 and 5.2 mm for M5, and pole pitch is 18 mm or 25 mm, specified at order.

Q: Can you produce other pole counts or hole patterns?

A: Yes. Standard supply is the 5-pole bar in cartons of 50 or 100 pieces. Pole counts of 3P, 4P, 6P, 8P, 10P and 12P, alternative hole patterns and non-standard lengths are produced to your drawing under OEM terms; MOQ depends on the configuration and any tooling.

Q: What about testing, packaging and delivery?

A: Plating thickness, hole position and torque are checked per batch. Units ship in standard export packaging from Ningbo or Shanghai ports, with a 12–24 month quality guarantee from shipment date. Send your drawing and quantity for a quote within 24 hours.