Essential Requirements in IEC 61010-1 Second Edition

Moe Lamothe, P.Eng, Lamothe Approvals Inc.

IEC 61010-1, First Edition was published in 1990 with CSA publishing their version (C22.2 No. 1010.1) in 1992. UL published three versions: UL 3101-1 to cover Electrical Equipment for Laboratory Use, 3111-1 to cover Electrical Measuring and Test Equipment and 3121-1 covering Process Control Equipment. 

UL has since renumbered their standards as indicated in the table below.   The Second edition was published by IEC in 2001, UL and CSA followed with their publications in 2003.

The scope of 61010-1 specifies.... general safety requirements for electrical equipment intended for professional, industrial process, and educational use, including equipment and computing devices for:

·      measurement and test

·      control

·      laboratory use ...

The scope also makes it clear that this standard does not apply to Information Technology Equipment. In fact, it also states that computing equipment that falls under the scope of 60950 and which complies with that standard can be used with equipment within the scope of this standard.

This is generally interpreted to mean that no additional testing is required even if the computing device is built into the 61010-1 equipment. One common item is power supplies approved to 60950, which are often used in 61010-1 equipment.

Because 61010-1 covers a wide range of equipment used in a variety of conditions greater reliance was placed on testing. The actual standard is far smaller than 60950 but the required tests to show compliance are significantly more onerous.

Creepage Distance and Clearance

The requirements of 61010-1 are based on the same set of creepage distance, clearance and environmental considerations as 60950-1, however, different values will be required depending on which standard is used for evaluation.  In general, the requirements for 60950-1 are more stringent than 61010-1, however, this is not always the case.

Installation Manual

Most standards make reference to the operator’s manual. 61010-1 makes review of the manual essential. Before testing and examination of the equipment can commence it is essential that the operating altitude and operating ambient be carefully considered.

The standard contains correction factors for increased clearances (not creepage distances) when the equipment is specified for use above 2000m.

The difficulty is that many products use power supplies tested to 60950-1 and these typically are not examined for the additional clearances required at higher altitude.

You need to give careful consideration to your specified altitude since this can cause significant problems in determining the acceptability of components.

Humidity Conditioning

The humidity test is generally considered less severe than the test used in 60950-1 in that the unit is conditioned at 40°C for 48 hours and then left at room ambient for 2 hours before testing and the test is at a lower voltage. The difference is that the entire unit must be put in the humidity chamber - a significant problem for large equipment.

Temperature Rating

All maximum temperatures are based on an ambient of 40°C although tests can be conducted at room temperature and the appropriate correction applied. If you specify a higher ambient than 40°C, this is used for the allowable temperatures.  

Circuit Separation

61010-1 has provided examples of circuit types that can be used to determine when basic, reinforced or double insulation is needed.

The definitions are the same as other international standards except that functional insulation is not specified (although a note is provided that basic insulation may serve for functional purposes). As such, there is no minimum spacing specified between line and neutral conductors on a PC board.

A consequence of the elimination of operational insulation is that you treat each circuit type as a block but you do not need to look at the spacing internal to that circuit. In lieu of operational insulation, spacing considered substandard can be shorted. As long as there is no hazard created, it is acceptable. This means there is no spacing specified between ‘hot’ and ‘neutral’.

Application and Use

Process control and specialized laboratory equipment was often not approved in the past since the end user relied on the manufacturer to provide safe equipment. The emergence of the  marking has changed this! 

Moe Lamothe is the president of Lamothe Approvals Inc. (Georgetown, ON, Canada). He can be reached at info@lamotheapprovals.com.

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Prepared May 2003