One significant difference between the North American standards approach and the IEC style we are more familiar with, is the way in which compliance with the standards is declared. In Europe, once a product or system carries the CE mark, (which is mandatory) then it can be placed onto the market without further consideration. The CE mark is the product’s “passport” to European acceptability.
Across the Atlantic, the CE mark is neither recognised nor required. Every machine, control system or piece of industrial plant, will be inspected prior to installation by an entity known as the “Authority Having Jurisdiction” or “AHJ”. The end user at the site is compelled, by law, to arrange this inspection, which will ensure compliance with the relevant standard.From an electrical perspective, the AHJ take as their starting point, the National Electrical Code (NFPA70) which is used in every state of the USA. When it comes to detailed aspects of the equipment, then the NEC contains internal cross-references to other, specific standards. For example, control panels are referenced to (UL508A), machinery to (NFPA79) and so on. This is known as “Incorporation by Reference” and means that whoever built the equipment, must have read, understood, and complied with each relevant standard as they went along.
And that’s not all…Things like our familiar ingress protection standards “surface mounted isolators must be to a minimum of IP55” are not recognised either. The USA came out of the traps much faster than we did in Europe in terms of standardisation of such things, and whilst we in the UK were still referring to enclosed devices as “weather-proof” they had already long established the system of “NEMA Types”, which standardised the testing in much the same way that our “IP” system does now. But again, caution is required here. The NEMA Types and the IP standards broadly cover the same subject, but they are not directly comparable. A table comparing the two ‘line for line’ can only be on a “near enough” basis. Compliance is only as the result of a test to the exact standard.
Are you keeping up?
Although it is not compulsory, some original equipment manufacturers have decided that the best way to demonstrate their fitness to be in this market is to acquire some formal accreditation of their ability to comply with the various North American rules.Unlike the CE, product marking is not something which can be self-certified. The North American system nominates a group of National Recognised Testing Authorities (NRTAs) who can assess vendor companies to the various standards they need.Helpfully, these companies operate under the umbrella of OSHA (the Occupational Safety and Health Authority) and the OSHA website lists them all.Only companies listed by OSHA have the legitimacy to offer accreditation to North American standards.
One thought-provoking statistic is that when compared to other European countries of a similar size, the UK has startlingly few such accredited companies; about 25% as many as Germany or Italy, and even fewer than the rather more modestly proportioned Netherlands! Since few would dispute the size and potential of the American market, the least one can say is that companies who successfully obtain accreditation have put themselves into a minority group from the perspective of competing for this business! No bad thing in itself.
As an occasional (and sluggish) cyclist, I know that the decision to get fit for anything requires some commitment. Getting fit for the North American market is no different. But as we all find when we decide to do something and take the first steps down the road, there is a mass of helpful, freely-available material and support to keep you on track and get you across the finishing line. If you would like to learn a little more about we at Rockwell Automation can offer on this subject or to download a PDF white paper, then go to http://www.rockwellautomation.com/en_UK and search ‘North American Standards’.
Author profile:
Ian Harwood is team leader, UK and Ireland – Industrial Components at Rockwell Automation
