The LV-Directive (2014/35/EC)

As all ce-related directives this is a new-approach directive, which means that only main requirements (essential requirements) are required. The LV-directive shows the way of showing compliance to the main requirements. The manufacturer may assess the safety of its product or apparatus by applying a standard from the list of Harmonized Standards

In addition since june 2016 a risk analysis is required.

 

Manufacturers declaration

The manufacturers declaration consists mainly of a liability statement (Declaration of Conformity DoC) made up by manufacturer or importing agent in which he accepts the legal consequences (liability) for conformity of its equipment  to the essential requirements from the LVD. The manufacturer is granted permission to do the assessment himself, or let the testing be carried out by any test-house. Using this route the manufacturer is strongly suggested to use the so-called Harmonized Standards for type testing, although in absence of these any other safety standard or no standard at all may be applied. 
Harmonized  standards, especially created for this purpose and modified existing standards are published in the official newspaper of the EC (OJEC), and in the official journals of all EC-members.

        

Purchase a model ce declaration of conformity    


Technical Construction File  (TCF).

In order to prove compliance to the essential requirements of the LVD one has to make up a Technical Construction File. This includes all safety related topics, such as precautions, instructions, test reports and everything necessary to identify the apparatus, such as circuit diagrams, mechanical drawings and detailed part lists. The mandatory risk analysis may be part of this file.

The LVD is not  just limited to electrical shock and insulation only. 

Once an apparatus falls into the scope of it, many other aspects of safety like fire hazards, mechanical hazards, radiation and chemical hazards are part of the approval procedure.

 

Basic Safety Concepts

Intended Use

Most manufacturers do know exactly what their product does or can, and therefore forget to write it down. Defining the intended use of the product is the best way of starting to evaluate your products safety. What exactly is its function, and who is meant to use it.

Operator access or service access

The areas in your equipment that are not meant for the user, but for service only, require different (relaxed) safety measure as those available to anyone By clearly defining those areas, and preserving their access with a tool or key, you improve the safety process.

Protection against electrical shock

Electrical safety is implemented using the concept of double safety layers:

1. Insulation + Grounding

2. Insulation + Extra Insulation (double or re-enforced insulation)

Any part at  hazardous voltage should be separated from the operator/user by 2 layers of safety as specified under 1. or 2. In addition to this the failure of one layer may not  affect the initial safety of the equipment. Operator safety must be achieved with one layer only. The approach of testing where one layer of safety fails  is called SINGLE FAULT TESTING. Evaluated are the effects of (among others) :

  • loose wire,

  • defective components,

  • loss of protective ground connection

  • misuse of equipment

Misuse (foreseeable abuse) of an equipment is also considered as a single fault.

Safe components

The LVD approval procedure is concerned with the safety of an apparatus, based on the utilization of safe and approved components in all applicable circuits (most important  in the mains circuit). This implies that all parts having a safety function need an examination to their specifications and (if applicable) need a ce-declaration (or better) available, before they are  allowed in the construction of an apparatus. it does definitely NOT mean that an equipment built with safe components is a safe apparatus. This is a very common mistake.

Proving component safety

Component manufacturers in generally are not very cooperative  in producing accurate declarations, as making up a ce-declaration of conformity involves direct liability of the manufacturer for the safety of its components .  A UL, CSA or VDE declaration -although very valuable- is a testimonial declaration and not a manufacturers declaration: less liability for the manufacturer is involved. Most US originated components lack sufficient component safety (for use at 230 Vac) due to the difference in mains voltage. Although manufacturers may specify a component as being suitable for 230 Vac, this does not imply that the same component is safe at 230 Vac. In order of relevance we require safety certificates from (for your applied components with a safety function)

  • Any recognized European test house with certificate (KEMA, NEMKO,VDE etc),

  • CE marked component with Declaration of Conformity,

  • UL or CSA marked components with proof of approval for 250 Vac,

  • Not certified or manufacturer certified components.
    (applying components from this category may lead to extra test costs)

Safety Function

What components do have a essential safety function ? In general, all components carrying mains voltage and all components carrying a hazardous voltage to the operator have a essential safety function. Even more general, all components carrying any hazard in them may qualify as such. An example may a a big capacitor or a battery.

Other requirements

Many more requirements exist considering hazards associated with heat, fire propagation, radiation, mechanical hazards (sharp edges), short circuits, leakage current (touch current) and more.

The electrical safety test procedures are not to be underestimated !


Harmonized standards

This list of standards is an ever increasing subset of world-wide existing standards, that due to their way of defining test-methods, limits and susceptibility criteria, are very well suited for testing by the manufacturer himself, or by any test house using the right equipment.

This list of standards is updated approximately  once a year.

 


Routine testing

The Declaration of Conformity is most often based on one sample of a "type tested product" that ideally should be identically reproduced in series. In order to maintain safety in real life production, some quality control is imperative. The LVD specifies the requirement of such a scheme.  Therefore each and every  produced apparatus must be verified for a number of essential parameters -composed by your test house- such as functionality, dielectric strength , the grounding qualities and potential pitfalls created by foreseeable mistakes in production.This focuses the attention on those faults that are easily made without being detected in functionality tests, and that would otherwise create a potential hazard to the operator. Examples are grounding clips, insulation barriers, warning labels, insulation (rubber) rings below ring core transformers etc.

In general, safety measures should be applied exclusively for the safety purpose, and should not share any task with  functionality , unless the safety measure  is very obvious. Safety features must be visible and easy distinguishable from functional features .Safety measures should not be compromised during normal operation and service.

Routine test must be logged, therefore serial numbering your equipment is required. Standards exist  for setting up these so-called routine tests:

  • House hold appliances    EN 50106
  • Hand held motor operated tools    EN 50144-1
  • Luminaries    ENEC 303
  • ITE equipment    EN 50116

Your test house will be helpful in selecting a routine type test protocol.

Most popular failures....

  • Insufficient insulation distances in connectors and printed circuit boards.

Although exceptions exist, the insulation between metal (accessible) parts and hazardous voltages (mains) must be no less of 4 mm and up to 8 mm in medical equipment. It's very easy to compromise these distances especially on printed circuit boards.

  • Unknown safety status of safety critical components

Not only equipment but also components must be tested for safety. Most components comply to international IEC or EN standards. Equipment brought to Europe often uses  UL or CSA approved components. 

You definitely have to make sure that your components are suitable and safe for European voltages and make sure they are sold to you with written proof of compliance. Just a catalogue page showing the ce mark in the corner won't do ! If it's writing "designed for (to) comply with .[standard]..  '  or "tested for [standard]...." , then you can be sure the part is not compliant.  Look for the phrase: "Compliant with [standard] " and then don't forget to check its the correct standard  and not an obsolete one.........! Correct part number and applied standard are best be mentioned on a manufacturer signed document.

  • Undefined parts

You must have seen that in your product's Bill of Materials:  many parts have no specified type or manufacturers name behind them. How can you be sure that this part performs the required function, and how can you declare liability for the safety of those parts ? Do not specify a distributor instead of a manufacturer.
Make sure you know who's manufacturing the components used in your equipment, and on which components the safety of your equipment and reputation of your brand relies.

  • Incomplete documentation

All equipment should ideally be  accompanied by the following documents:

  • Compliance declaration
  • Statement of origin
  • Safety manual/leaflet
  • Installation Manual
  • Operators manual
  • Service manual

Of all these parts  the safety part MUST be translated in the language of the country you are selling to. Some countries require other parts to be translated too. Several parts may be contained in one volume however, but we recommend a separate sheet for those safety aspects that require immediate attention when opening the box... should we mention why ??

Incomplete or inconsistent documentation

Does this sound familiar to you ?

  • The day your product is finished your sale department changes the name of the product.
  • The PCB files do not carry the products name and/or are undated.
  • Unused components are still present on circuit diagrams
  • Manual are unfinished, undated or not versioned.

Both the test agency and the authorities need to verify if the approved product is identical to that on the market. What will be the initial conclusion if name, version and date are not consistently used?

Let us quote you for your product and get all this and more taken care of....