Insights

Insights

THE QUESTION
Machine and control panel manufacturers often wonder which Electrical Standard shall they follow for the CE Marking of Industrial Control Panels. 
There are different schools of thought: some people think that the IEC 60204-1 Safety of machinery – Electrical equipment of machines – Part 1: General requirements is the only one applicable standard, and others think that IEC 61439-2 Low-voltage switchgear and controlgear assemblies – Part 2: Power switchgear and controlgear assemblies is fully applicable as well.


CONSIDERATIONS
The doubt is justifiable because neither of the two Standards could be classified as the Product Standard for the industrial control panels. 
IEC 61439-2 is the standard for low-voltage switchgears, while IEC 60204-1 provides requirements and recommendations related to the electrical equipment of machines so as to guarantee: 
-    Safety of person and property; 
-    Consistency of control response; 
-    Ease of maintenance. 

The latter is more an installation Standard than a product Standard, equivalent to NFPA 79 for the USA market. The IEC 61439-2 is the product standard closer to the concept of industrial control panels despite the Standard is written having switchgears in mind.
In the USA the situation is clear: the product standard for switchgears is UL 891, and the one for industrial control panel is UL 508A
 

Machinery Directive
Starting from 1 January 2021, United Kingdom is officially outside of the European Union; the new UKCA mark will substitute CE mark for products placed on market in Great Britain (England, Wales and Scotland). The table below clarifies some of the terms used in this article.  
UL and CSA Conformity
Manufacturers of industrial control panels to be installed in North America often don't know which electrical tests to submit their products to.
Machinery safety
IEC 60204-1 VS IEC 60445: green-and-yellow functional grounding conductor VS pink functional grounding conductor.
UL and CSA Conformity
SPDs mandatory in Industrial Control Panels? A highly debated issue both in North America and Europe.
Functional Safety
THE DOUBT: Should the Reset button in a machinery be handled by a safety module, or can it be one of several inputs to the Automation PLC? The question can be rewritten in a more correct language by asking if the Reset is a Safety Function.
Machinery safety
Are you new in the Machinery Technical Standard world and do you feel a bit lost with the terminology?
ATEX Risk
THE DOUBT Do Equipment containing potentially explosive atmosphere and installed in safe areas, fall under the ATEX Directive 2014/34/EU? CONSIDERATIONS Consider for example a Mixer, that contains a potentially explosive atmosphere but completely closed when it works. It is installed in a non-classified area while the manufacturer, during the risk assessment, has defined a Zone 0 inside it. Shall it be CE Marked Category 1 according to the ATE
UL and CSA Conformity
Switchgears and switchboards are intended to ensure the power distribution to other devices, boards and panels. Although these cabinets are different, they are often easily confused and so it is important to know how to distinguish them.  
UL and CSA Conformity
  There are several differences between the North American and International electrical standards (published by IEC). One of those differences is the way they deal with the short circuit aspects. There are five important parameters, linked to a short circuit current, that machinery manufacturers should know. The first two are referring to the value of short circuit current that the distribution network can generate in any point, the last three
Machinery safety
THE DOUBT: Most of us know that Light Blue is the colour of the neutral conductor inside an industrial control panel. The doubt is the colour of the “common conductor” on the secondary of either a Power or a Control Transformer. CONSIDERATIONS: In order to clarify the matter, it is important to understand when a conductor can be defined as a Neutral Conductor. IEC 60445 helps us in that: [IEC 60445:2018] 3.8 neutral conductor: conductor electr
Arc Flash
THE QUESTION On the electrical standard, we often read that the assemblies and/or the electrical equipments in general shall provide a degree protection against contact with live parts at least IPXXB or IP2X according to IEC 60529. What do these codes means and which differences exist between the degree protection IPXXB and the degree protection IP2X?  
Machinery safety
Since their incorporation, the Harmonized Standards have been technical directives of optional application, which can be used by manufacturers to certify their products. However, recent judicial developments could change the legal value of the Standards and the whole European process of creating standards.
Machinery safety
There is often confusion as to whether or not type B residual current devices are required to protect lines in which variable speed drives are used to control asynchronous motors: let's clear up any doubts!
ATEX Risk
THE DOUBT: My Machine will be installed in Zone 2 (22). Do I need to involve a Notified Body? CONSIDERATIONS: Here what the ATEX Directive 2014/35/EU states regarding the CE Marking of the machine: [2014/35/EU] Article 13 - Conformity assessment procedures The procedures to be followed for assessing the conformity of equipment and, where necessary, the devices referred to in point (b) of Article 1(1) shall be as follows: […] for eq
Functional Safety
The second edition of IEC 62061 was published on the 22nd of March 2021. The work for the new edition started in early 2016. Some years before, a working group was established, with the assignment of writing one common standard (called ISO/IEC 17305) for Functional Safety, combining ISO 13849-1 and ISO 62061. Unfortunately, the new standard did not see the light. When the MT 62061 (maintenance team as they are call it in IEC) met the for first
Machinery safety
A new ISO standard has to go through six maturity stages: (10) PROPOSAL STAGE: we are at the very beginning: the very first document is called new work item proposal (NWIP) and it is submitted to the committee for vote. The person being nominated as project leader is named on the Form. If there are possible complications around copyright, patents or conformity assessment they should be raised at this early stage. This stage can be skipped for re
Machinery safety
Is an enclosure interlocking required for industrial control panels? That is a strongly debated topic and not yet fully understood: let's clear this out.
Process Safety
THE DOUBT: What is the difference between a Proof Test and a Diagnostic Test? CONSIDERATIONS: The Proof Test concept is coming from IEC 61508 and it is important, especially for the Safety Instrumented Systems (SIS) used in Low demand. In Low Demand, a pressure transmitter used in safety applications may never be needed, or very rarely. Let’s say that a high pressure is detected by a Safety System, in a particular application, every 6 years. F
Gas Fournaces CE Marking
THE DOUBT Technical standards often require external leakage test on components to be used in a gas plant, or even on the plant itself; however, the measurement of gas leaks is not always easily feasible. So how can we run this test? CONSIDERATION Leakage test is essential for each of the components that make up a gas plant: each gas leak increases the risk of fire and explosion. To help manufacturers and users in risk management, product s
Arc Flash
  THE DOUBT In the design of the electrical system, how can I distinguish which of the metal parts is an exposed conductive part? Is grounding all the metal parts a valid safety measure, or can it even be counterproductive?   CONSIDERATION The difference between exposed conductive part and a common metal body can be un unclear. For an exact definition of exposed conductive part we refer to IEC 61141, standard for the design of low voltage syst
Arc Flash
  DOUBT We know that high and low sensitivity Residual Current Devices (RCDs) are divided according to the current IΔn (nominal differential current of intervention) which triggers the protection, respectively ≤30 mA for the former and >30mA for the latter. But is that really the only difference?   CONSIDERATION Residual Current Devices physically monitors the vector sum of phase currents and neutral, verifying that it is zero, as it should
Arc Flash
  Circuit breakers are meant to protect the circuit from overcurrents, which can be divided in two categories: overload, i.e. a current that settles in an electrically healthy circuit (for example, an electric motor that moves a shaft with defective or worn out bearings is forcibly slowed down and absorb more current). short circuit, i.e. a current produced by a negligible impedance failure between two parts of the circuit (examples are shor
Arc Flash
  THE DOUBT What are the differences between RCDs and Type G Ground Fault Protections?   CONSIDERATIONS Among possible causes of electric shock there are the Indirect Contacts: following a Ground Fault, for example caused by defective insulation, the current can flow through an exposed conductive part, and a person may die in case he touches it. Both type G and Residual Current Devices operate to protect against Indirect Contact (Fault Protec
Machinery Directive
After a few years in the “kitchen”, the first draft of the new machinery directive has seen the light in April 2021. The reasons for the new edition are the following: The MD does not sufficiently cover new risks originating from emerging technologies. Think for example to the human-robot collaboration. Insufficient provisions for high risk machines. Today, in case of the availability of a C-Type standard, Machineries in Annex IV do not requi
Arc Flash
  THE DOUBT Can the machinery manufacturer require the user to install a Fuse or a Circuit Breaker to protect its Electrical Equipment? Can he require the user to install a Residual Current Device to protect the user from Indirect Contacts (Fault Protection)?    CONSIDERATIONS  Electrical Energy has two main risks: -    Electric Shock -    Fire The standard requires the machinery manufacturer to deal with both with the following language:
Machinery Directive
THE DOUBT: What is a Substantial Modification of a Machinery and what are its implications?   CONSIDERATIONS:  Up to 2021 there was no definition of a Substantial Modification of a machinery. Moreover, nothing was stated on the implications of a substantial modification done by a different entity than the original manufacturer. The subject was discussed during the revision of the text of the machinery directive and, in the first draft, publi
Machinery Directive
Historically, EU legislation for goods has progressed through four main phases: the traditional approach or ‘Old Approach’ with detailed texts containing all the necessary technical and administrative requirements, the ‘New Approach’ developed in 1985, which restricted the content of legislation to ‘essential requirements’ leaving the technical details to European harmonised standards. This in turn led to the development of European standar
Machinery safety
Harmonized standards play an important role in the EU Legislation for the CE Marking of Machineries. ISO classifies the 800+ International technical standards harmonised to the machinery directive in 3 categories: type-A standards (basic safety standards) giving basic concepts, principles for design, and general aspects that can be applied to machinery; type-B standards (generic safety standards) dealing with one safety aspect or one type of
Machinery Directive
THE DOUBT: If an employer makes a machinery for use in its own factory, does he have to CE mark it? CONSIDERATIONS: Let’s first clarify two important concepts: 1- PLACING ON THE MARKET [Machinery Directive 2006/42/EU: Whereas:]  (h) ‘placing on the market’ means making available for the first time in the Community machinery or partly completed machinery with a view to distribution or use, whether for reward or free of charge; 2-PUTTING INTO
Process Safety
THE DOUBT : What does it mean that a Safety Control Systems is operating in High or in Low Demand and why is it important to know it? CONSIDERATIONS: Using an analogy with urban mobility, the characteristics of a car that is used every day should be different from those of a car used once every four years. In both cases we are looking for a reliable car; if we do not specify that we want to use the car every four years it will be likely that whe
Machinery safety
  As we know, the compliance to the Harmonized Standards guarantees the presumption of conformity with the EHSR (Essential Health and Safety Requirements), compliance which is necessary and mandatory to obtain the CE marking of the products and the resulting free movement on the market. The application of Harmonised Standards is not an obligation, it is only a possible method to ensure the safety of products; in practice, Harmonised Standards ar
Machinery Directive
  The Guide to the Machinery Directive 2006/42/EC has been updated in October 2019. It contains a number of clarifications and corrections to the concepts of “safety components” and “partly completed machinery”, and some edits to ensure coherence with the Low Voltage Directive (LVD) Guide. There are also two new paragraphs about the machinery control units (§417) and safety components which are considered to be logic units (§418).  In the Atta
Machinery safety
THE QUESTION Often the manufacturer has doubts about what should be indicated in the Instruction manual. One of the aspects is whether it is necessary to report the spare parts list. What obligation does the manufacturer have in this regard? CONSIDERATIONS The drawing up machinery instructions is an obligation of the manufacturer. Point 1.7.4 of the Machinery Directive 2006/42/EC deals with the obligations to be met regarding the Instructions fo
Machinery Directive
Before placing machinery on the market and/or putting it into service, the manufacturer shall draw up the EC Declaration of conformity in accordance with Machinery Directive 2006/42/EC.  When a machine, that falls within the scope of the Machinery Directive, has an electrical supply within the voltage limits of the Low Voltage Directive (between 50 and 1000 V for alternating current or between 75 and 1500 V for direct current), it must fulfil the
Machinery safety
Machinery safety is often dealing with 2 areas: -    A safe area, free of hazards -    A dangerous one Historically, the term used to identify the dangerous area is “Hazard Zone” ISO 12100 definition: 3.11 Hazad Zone (danger zone): any space within and/or around machinery in which a person can be exposed to a hazard. Link to the concept of hazard zone is the term Safeguard and Safeguarding (ISO 12100, definitions) 3.26 Safeguard: guard or protect
Machinery safety
  According to EN 60204-1 "Safety of machinery - Electrical equipment of machines Part 1: General requirements", there are three categories of stop functions:   Stop Category 0: stopping by immediate removal of power to the machine actuators (i.e. an uncontrolled stop); Stop Category 1: a controlled stop with power available to the machine actuators to achieve the stop and then removal of power when the stop is achieved; Stop Category
Machinery safety
THE DOUBT By working everyday together with manufacturers of machineries, we get frequentily asked the question "is it mandatory to give to our customer the Instruction Hanbook of the machine in papery format?"   CONSIDERATIONS Right now, the Guide of the Machinery Directive 2006/42/EC clarifies that the manufacturer of a machine must provide the Instructions Handbook and the declaration of conformity of a machine in papery format. This is a
Machinery Directive
THE QUESTION The manufacturer often asks questions about the free circulation of machines in countries outside the EU.  Do the same EU principles apply to Turkey? CONSIDERATIONS The Machinery Directive applies to machinery or partly completed machinery placed on the EU market. It does not apply to products manufactured in the EU with a view to being placed on the market or put into service in countries outside the EU, although certain of these c
Machinery safety
THE DOUBT When analysing switchboards, we sometimes notice that the main disconnector-switch is installed directly on the door of the switchboard, instead of on the bottom plate, with an external operating handle rod. But is it permissible to install such a switch-disconnector on the door of a switchboard? CONSIDERATIONS Disconnecting an electrical circuit means interrupting its electrical (galvanic) continuity in a reliable manner, in order t
Machinery safety
If you deal with Machinery Safety you may wonder what Whole Body Access means. That is a relatively new terminology (this article was written in 2019). It indicates the risk that a person remains inside a safeguarded space. Exposure to a hazard represents a potential risk when a person gains access to a hazard zone beyond a safeguard space.   A hazard arises when the person is no longer detected and the hazardous situation machine function resum
Machinery safety
The CE marking indicates the conformity of the product with the Union legislation applying to the product and providing for CE marking. The CE marking is affixed on products that are placed on the EEA and Turkish market, whether they are manufactured in the EEA, in Turkey or in another country. The CE marking is a key indicator (but not proof) of a product’s compliance with EU legislation and enables the free movement of products within the Eur
Arc Flash
Two main International Standards supports the use of “Zero Energy” to reduce hazards in Machineries: ISO 14118: Safety of machinery - Prevention of unexpected start-up (Latest edition: 2017) ANSI ASSE Z244.1: The Control of Hazardous Energy Lockout, Tagout and Alternative Methods (Latest Edition: 2016) Hazardous energy includes energies generated by Electrical, Pneumatic Hydraulic, gravity, chemical, combustion gasses (Methane) etc…
Machinery safety
The assessment and risk reduction process is detailed in various standards. An important aspect of the risk reduction methods suggested by the standards concerns the reduction of energy levels. When possible, access to a segregated area should be carried out at zero energy with the elimination and isolation of hazardous energy (preferred method to reduce the risk). However, some activities require partial or total energization to be performed an
There is no “Collaborative Robot”. That is one of the first statements you hear from people working in Collaborative Robotics. The reason is because the robot can be designed for a collaborative task, but it is the Application that makes the “Robot Collaborative”. The reference standard for Collaborative Application is  ISO/TS 15066:2016 - ROBOTS AND ROBOTIC DEVICES -- COLLABORATIVE ROBOTS Not only for the unfortunate title, the standard will b
Machinery safety
Among the commands of a machine, probably, the emergency stop is the most visible one; however it is not the easiest to understand. The reference standard is the ISO 13850, whose latest edition was published in November 2015: "Safety of machinery - Emergency Stop Function – Principles for design". The definition is (§3.1): ”function which is intended to avert arising or reduce existing hazard to person, damage to machinery or to work in progres
Arc Flash
The Earth Fault Loop includes the Load, the bonding conductor, the earthed (Grounded) neutral point of the tranformer, the source line winding and the live conductor from the source to the load. The earth fault loop impedance verification is performed to prove the correct operation of the protective device in order to protect in caso of indirect contats. The aim is to check that, in case of a ground fault, the related fault current is strong eno
Gas Fournaces CE Marking
The Gas Train is a part of a combustion system, featuring the components that carry the fuel from the network (or from the tank) to the burner. A gas train can feed one or more burners. The designer must consider the Standard EN 746-2. This Standard states the requisites that guarantee the safety of people and equipment and the correct functioning of the system. It also indicates which safety devices should be used.
UL and CSA Conformity
UL 508A is the reference standard for the Industrial Control Panels in the USA. The basis are the safety rules prescribed by the National Electrical Code (NEC). The NEC has ARTICLE 409 dedicated to the Industrial Control Panels, but it contains few details. That is why in 2001 UL508A was issued. Latest update of the standard is Augusto 2016. UL 508A is applicable to Machinery Electrical Panels only. In case a Machinery has a distribution panel i
Machinery safety
Machinery Safety is probably the main leverage that can reduce the number of deaths and injuries in the work place. In the European Union machinery is a contribuing factor in more then 300.000 injuries involving more than 3 days off work, according to data (2008) from the European Commission. In China, 30% of Injuries treated in hospital emergency departments are machinery related (data from 2011). Annually there are 65.000 injuries involving day
Arc Flash
Overload relays typically operate on an inverse time curve where the tripping time becomes less as the current increases. They are rated by trip class. Trip class specifies the length of time it will take for the relay to open in an overload condition. In Europe the shape of the overload relays tripping curves are defined by ANSI or IEEE standards. A few examples are: ANSI Extremely Inverse, Very Inverse, Inverse, Short Time Inverse; or IEEE Mod
Arc Flash
A GFCI (Ground Fault Circuit Interrupter) is the American equivalent of the High Sensitivity Differential protection or "Salva Vita" in Italian. It detects if the current is flowing where it should not (ground fault) and shuts off the power. It triggers at 6mA (and should not trigger below 4mA). Touching a live conductor that is protected by a GFCI will still cause a shock, but the GFCI will open the circuit before it becomes lethal. They are us
Machinery safety
Steel is the world's largest recycling system. Steel used in everyday life can be melted down to become new steel products. In one shell, scrap is preheated using natural gas, while in the other shell, scrap is melted using electric and chemical energy. Then, the molten steel is tapped into ladles. At the ladles metallurgy furnaces, steel chemical composition and temperature is fine-tuned. Alloying elements are added, the carbon content is
Machinery Directive
Standards in Europe date back to the late 1800s. The International Electro technical Commission (lEC) was founded in 1906 to establish safety specifications for energy and electrical products and protect consumers and the environment. lEC standards are prepared with consultation from technical committees (TC) in over eighty countries. These committees have representation from many interested parties, including, but not limited to, manufacturers,
Machinery safety
The Alarp principle recognizes that there are three broad categories of risks: 1. Negligible risk: Broadly accepted by most people as they go about their everyday lives, these would include the risk of being struck by lightning or of having brake failure in a car. 2. Tolerable risk: We would rather not have the risk but it is tolerable in view of the benefits obtained by accepting it. The cost in inconvenience or in money is balanced against the
UL and CSA Conformity
The world of electrical installations is not always straightforward. Working on an international project electrical engineers are often bewildered by the extensive amount of electrical standards and wiring regulations which determines their decisions.  The world can be divided in two areas for what concern electrical standards: NEC countries and IEC countries. IEC 60364 is a collection of documents that define fundamental principles, practices
Arc Flash
BS 7671: 2008 is the National Standard for most electrical installation work undertaken in the United Kingdom. It is also adopted by a number of other Countries in the World. The first edition of BS 7671 was published in 1992 when the British Standards Institution (BSI) adopted the IEE Wiring Regulations, 16th Edition and made it a National Standard. The British Electrotechnical Committee (BEC) is part of the British Standard Institution (BSI) an
Arc Flash
Many existing and new industrial facilities include multiple generators operating on plant distribution buses at the medium-voltage level. The fault type to which stator windings are most often subjected is a short circuit to ground. Many incidents of severe damage to bus-connected generators from stator ground faults have been reported in recent years. It has been recognized by recent studies that the generator damage is caused more by the grou
Machinery safety
If you are a machinery manufacturer or exporter to the European market you might have assumed that shipping products to Europe was a rather simple operation, but found yourself confused by the complex maze of European Conformity laws and regulations. Don't worry, the matter is not so complex. First of all, unless you produce Machineries falling under Annelx IV, you do not need any Notified Body, but a good Consultant on the subject. Second
Gas Fournaces CE Marking
The electric arc furnace operates as a batch melting process producing batches of molten steel known "heats". The electric arc furnace operating cycle is called the tap-to-tap cycle and is made up of the following operations: Furnace charging Melting Refining De-slagging Tapping Furnace turn-around Modern operations aim for a tap-to-tap time of less than 60 minutes. Some twin shell furnace operations are achieving tap-to-tap times of 35
Arc Flash
Currently the NEC in Article 100 defines the terms "ground" or "grounded" as "connected to the earth or to some conducting body that serves in place of the earth." Yet, the NEC often uses the term "ground" when it really means "bond" (connected to an effective ground-fault path to clear a fault) [250.2 and 250.4(A)(5)]. The two concepts have quite different meaning. Grounding - Grounding metal parts to the earth in premises wiring is only useful
Machinery safety
Occupational Safety and Health Administration (OSHA) The Occupational Safety and Health Act (OSHA) passed in 1970 to provide safe and healthy working conditions. Part 1910 of the 29th Code of Federal Regulations (CFR) gives specific standards. Subpart O of Part 1910 sets standards for machinery and machine guarding, and divides into Part1910.211 to Part 1910.219. Standard No.   Title 1910.211          Definition 1910.212          General requir
UL and CSA Conformity
The reference standard in Canada for the Machinery Safety is the Technical Norm Z432-04. This Standard is intended to be applied to newly manufactured and newly installed machinery. The aim of this Standard is to promote a high standard of machinery safety during use.  It specifies requirements for the design, manufacture (including remanufacture and rebuilding), installation, maintenance, operation, and safeguarding of industrial equipment to 
Machinery safety
Safety standards define safety as freedom from unacceptable risk. The most effective way to eliminate risks is to design them away. But as risk reduction by design is not always possible or practical, safeguarding with static guards are often the next best option, and for several reasons.  Stopping a machine quickly and safely, not only reduces risk but also increases machine uptime and productivity compared with abrupt safety stops. At the same 
Machinery safety
The main alternatives for protection of the users of fixed ladders against falling from a height are: •    Safety cage •    Guided type fall arrester on rigid anchorage line (fall arrester) The reference standard is ISO EN 14122-4.  In case of an overall falling height more or equal to 3000 mm, the ladder shall be fitted with a fall protection device. What is specified in the standard is that, in general, it is advisable to adopt the safety cag
Machinery safety
THE QUESTION Machine and control panel manufacturers often wonder which Electrical Standard shall they follow for the CE Marking of Industrial Control Panels.  There are different schools of thought: some people think that the IEC 60204-1 Safety of machinery – Electrical equipment of machines – Part 1: General requirements is the only one applicable standard, and others think that IEC 61439-2 Low-voltage switchgear and controlgear assemblies – Pa

Safety in Collaborative Robotics

There is no “Collaborative Robot”. That is one of the first statements you hear from people working in Collaborative Robotics. The reason is because the robot can be designed for a collaborative task, but it is the Application that makes the “Robot Collaborative”. The reference standard for Collaborative Application is  ISO/TS 15066:2016 - ROBOTS AND ROBOTIC DEVICES -- COLLABORATIVE ROBOTS Not only for the unfortunate title, the standard will be included in the new edition of 2 important standards on Robots: ISO 10218-1: Robotics — Safety requirements for robot systems in an industrial envir