Copper Terminal Bars — Bus Bars and Terminal Connection Bars

Jamnagar Brass Components manufactures and exports precision copper terminal bars — also known as copper bus bars, terminal bus bars, or conductor bars — for use in electrical switchgear, control panels, transformer terminal boards, generator output panels, motor control centres (MCCs), and power distribution systems. Our terminal bars are produced from high-conductivity ETP copper (C11000) to custom dimensions, with punched or drilled holes to your bolt pattern layout, and with optional tin plating for oxidation resistance and improved contact performance.

What is a Copper Terminal Bar?

A copper terminal bar is a flat or profiled bar of high-conductivity copper, pre-drilled or punched with a series of bolt holes at specific pitches, used to provide multiple termination points within a panel, switchboard, or transformer terminal box. Unlike a main power bus bar (which carries current from one end to the other), a terminal bar is a short connection bar onto which individual cable lugs are bolted, providing a centralised, accessible termination point for each circuit or cable in the assembly.

Copper Grade for Terminal Bars — Material Standards

Grade	UNS (USA)	EN (Europe)	BS (UK)	IS (India)	Conductivity
ETP Copper C11000	C11000	CW004A	C101	IS 191 Grade A	≥100% IACS
OF Copper C10200	C10200	CW008A	C103	Cu-OF	≥100% IACS
Copper Flat Bar	ASTM B187	EN 13601	BS 1433	IS 1897	min 99.9% Cu

Types of Copper Terminal Bars We Manufacture

Single-Row Drilled Copper Terminal Bars

Flat copper bars with a single row of holes at equal pitch (typically 25 mm, 30 mm, or 40 mm centre-to-centre) for M6, M8, or M10 terminal bolts. Standard sizes from 20×3 mm to 100×10 mm cross-section, in lengths from 100 mm to 2000 mm. Supplied bright or tin-plated.

Double-Row and Multi-Row Copper Terminal Bars

For high-density cable termination panels, we produce double-row and triple-row terminal bars with offset or staggered hole patterns to accommodate multiple conductors per phase in switchgear and MCC assemblies.

Transformer LV Terminal Bars

Heavy-duty copper terminal bars for transformer LV terminal boards, with elongated slots or NEMA-pattern holes for connecting high-current cable lugs (185 mm² to 1200 mm²). Available with rounded or chamfered edges per transformer OEM drawings.

Earth and Neutral Terminal Bars

Pre-drilled earth (green/yellow) and neutral (blue/grey) copper terminal bars for consumer units, distribution boards, and industrial panel boards. Insulated mounting versions with bakelite or nylon insulators are available.

Generator Output Terminal Bars

Custom copper terminal bars for generator set output terminals — typically L-shaped or step-profiled — to connect generator windings to the output panel cable lugs in alternator end-shields and terminal boxes.

Solar Inverter and EV Charger DC Terminal Bars

Custom short DC terminal bars for solar PV inverter DC input connections, string combiner boxes, and EV charger DC bus connections where multiple input cable pairs terminate onto a single copper bar.

Applications of Copper Terminal Bars

• Switchgear and panel board cable terminations
• Motor control centres (MCC) and variable speed drive panels
• Transformer terminal boards (LV and HV)
• Generator output and AVR panel connections
• Distribution board earth and neutral connections
• Solar inverter and combiner box terminations
• UPS and battery bank DC bus connections
• Rail traction and rolling stock electrical panels

Why Choose Jamnagar Brass Components for Copper Terminal Bars?

• High-conductivity ETP copper — ASTM B187 / EN 13601 certified, ≥100% IACS
• Custom dimensions — any cross-section, length, hole pattern, and bolt size
• Precision drilling and punching — hole position tolerance ±0.3 mm, hole diameter ±0.1 mm
• Tin plating available — 8–15 µm bright tin per ASTM B545 for all stock and custom bars
• ISO 9001:2015 certified quality — dimensional inspection report with each order
• Fast turnaround — standard bars ship in 5–7 days; custom bars in 2–3 weeks
• No minimum order — from 10 pcs for custom terminal bars
• Competitive pricing — significant cost savings over US and European sourcing

Frequently Asked Questions — Copper Terminal Bars

Q1: What copper standard do you use for terminal bars?

We manufacture copper terminal bars from ETP copper flat bar per ASTM B187 (bus bar, rod, and shapes) for US customers, and EN 13601 (EN AW-1350 equivalent for copper) and BS 1433 (hard-drawn copper bus bar) for UK and European customers. All material has minimum 99.9 percent copper content and electrical conductivity of at least 100 percent IACS, confirmed by Material Test Certificate supplied with every order.

Q2: What cross-sections and lengths are available for copper terminal bars?

We manufacture terminal bars from 20 by 3 mm cross-section up to 120 by 15 mm, in any length from 100 mm to 3000 mm. Standard cross-sections include 20×3, 25×3, 30×5, 40×5, 50×6, 60×6, 60×8, 80×8, 80×10, 100×10, and 120×10 mm. Non-standard cross-sections are available with a minimum order quantity. We also supply L-shaped, T-shaped, and stepped profile terminal bars to customer drawings.

Q3: What are the current ratings for copper terminal bars?

As a guide per IEC 60439 in free air at 35 degrees Celsius: 20 by 3 mm carries approximately 125 A, 30 by 5 mm approximately 250 A, 40 by 5 mm approximately 350 A, 60 by 6 mm approximately 550 A, 60 by 10 mm approximately 800 A, 80 by 10 mm approximately 1100 A, 100 by 10 mm approximately 1500 A. For enclosed panel applications with reduced ventilation, derating factors apply. We can provide calculations for specific installations.

Q4: Can you supply copper terminal bars with insulated mounting?

Yes. Copper terminal bars are available pre-assembled with Paxolin (paper phenolic), Bakelite, or glass-filled nylon mounting insulators for direct panel mounting. Insulation classes of 600 V and 1000 V are available. Stud-mounted insulators with brass threaded inserts and clip-on rail insulators (compatible with 35 mm DIN rail) are both available. Insulated terminal bar assemblies are commonly used for neutral, earth, and phase terminal rails in distribution boards.

Q5: Do you supply tin-plated copper terminal bars?

Yes. Tin plating is standard on most of our copper terminal bar stock. Bright electroplated tin at 8 to 15 microns per ASTM B545 prevents surface oxidation, improves contact resistance at cable lug interfaces, and facilitates clean installation without abrasion of the copper surface. Heavy tin plating at 20 to 25 microns is available for coastal, chemical plant, or marine electrical panel applications.

Q6: What hole patterns and bolt sizes are available on drilled terminal bars?

Standard hole pitches are 25 mm, 30 mm, 40 mm, and 50 mm centre-to-centre in single or double row configurations. Standard hole sizes are M6, M8, M10, M12, and M16 through-holes, countersunk on one face to accept lug palm profiles. Hole position tolerance is plus or minus 0.3 mm, hole diameter tolerance plus or minus 0.1 mm. Custom hole patterns including NEMA two-hole pad (1-5/8 inch and 3-1/8 inch) are available.

Q7: Can you supply copper terminal bars for solar PV inverter and EV charger applications?

Yes. Custom short copper terminal bars for solar PV string combiner boxes, inverter DC input connections, and EV charger DC bus connections are a standard product. These typically require custom lengths, multiple hole positions per ANSI or customer bolt patterns, and tin plating. We supply these to manufacturers of solar inverters, combiner boxes, and EV charging stations in the USA and Europe.

Q8: What is the maximum operating temperature for tin-plated copper terminal bars?

ETP copper retains full conductivity up to approximately 200 degrees Celsius. Bright tin plating begins to melt at 232 degrees Celsius but re-alloys with the copper substrate during normal service above 100 degrees Celsius to form a stable tin-copper intermetallic. For applications above 150 degrees Celsius, silver-plated copper terminal bars are recommended as silver maintains its conductivity and resistance to oxidation at temperatures up to 400 degrees Celsius.

Q9: Do you supply earth and neutral terminal bars for distribution boards?

Yes. Pre-drilled copper earth terminal bars (green or uncoated) and neutral bars (sometimes supplied with insulating supports) for consumer units, main distribution boards, and sub-distribution boards are a standard product. We supply to BS 7671 (IET Wiring Regulations) compatible designs for UK customers and to NEC and UL 67 panelboard standards for US customers. Mounting insulators in 600 V and 1000 V classes are available.

Q10: What is the lead time for custom copper terminal bars?

For standard cross-sections in stock (20×3 to 100×10 mm): custom cut-to-length with drilling and tin plating in 7 to 10 working days. For non-standard cross-sections requiring extrusion or drawing: 4 to 5 weeks. For very large or complex profiles requiring special tooling: 6 to 8 weeks. Air freight to the USA takes 3 to 5 days. We also offer blanket order contracts with regular monthly releases for repeat production quantities.