IEC 62135-1:2015

Overview

IEC 62135-1:2015 - Resistance welding equipment - Part 1: Safety requirements for design, manufacture and installation - is the second edition (2015) international standard that replaces the 2008 edition. It applies to resistance welding and allied processes and covers single and multiple welding stations that may be manually or automatically loaded/started. This edition is a technical revision (including the Feb 2016 corrigendum) and updates electrical, insulation and thermal safety requirements for resistance welding equipment.

Key topics and technical requirements

The standard focuses on electrical and thermal safety measures specific to resistance welding equipment. Major technical topics include:

• Protection against electric shock: insulation, clearances, creepage distances (note: creepage values for pollution degree 4 were removed), welding circuit touch current and touch current measurement procedures (see Clause 6 and Annex C).
• Insulation and dielectric testing: defined Class II insulation requirements, dielectric test voltage interpolation rules (lower limit now 220 V) and insulation resistance/strength tests (Clauses 6.2 and 6.4).
• Supply network considerations: revised nominal supply voltages adopting IEC 60664-1 Table B.2 - affects required creepage/clearance distances (Annex A).
• Thermal requirements and heating tests: clarified heating test conditions, temperature measurement methods and limits for winding and external surface temperature rise (Clause 7).
• Mechanical and functional safety: requirements for abnormal operation, cooling system failures, stalled fan tests and overload testing (Clause 8).
• Marking and documentation: instructions, markings and terminal identification requirements (Clause 10, including 10.3 on terminal marking).
• Normative/ informative annexes: construction of supply terminals (Annex B), touch current measurement (Annex C), risk analysis examples for spot/projection/seam/butt welding (Annex E), and indirect contact protection guidance (Annex F).

Applications and practical use

IEC 62135-1 is intended to ensure safe design, manufacture, testing and installation of resistance welding equipment used in:

• Automotive and heavy manufacturing (spot, seam and projection welding)
• Electrical/electronic assembly plants using resistance welders
• Fabrication lines with automated/multi-station welding cells

Practical benefits:

• Enables manufacturers to design compliant welding machines and select appropriate insulation, clearance and protective measures.
• Helps safety engineers and test labs verify conformance through defined tests and measurement procedures.
• Guides installers and maintenance staff on marking, terminal layout and protection measures for safe installation and service.

Who should use this standard

• Equipment designers and manufacturers
• Component suppliers (transformers, electrodes, insulation systems)
• Test laboratories and conformity assessors
• Safety engineers, installation contractors and regulatory authorities

Related standards

• IEC 60664-1 (insulation coordination / nominal voltages) - referenced for supply voltage tables
• IEC 60085 (insulation temperature ratings) - used to review maximum temperatures for insulation systems

For manufacturers and safety professionals working with resistance welding equipment, IEC 62135-1:2015 is a primary reference for electrical and thermal safety design and compliance.