Five things you need to know about CE Marked Wire and Cable

Wire is sim­ple right? Maybe not! Here are the top five things to know when select­ing wire and cable prod­ucts for use in designs that will be CE Marked:

  1. Wire and cable prod­ucts sold in the EU must be CE Marked under the Low Volt­age Direc­tive, and MAY bear BOTH the CE Mark and the HAR mark. The HAR mark may only be applied by man­u­fac­tur­ers that have met the require­ments for the use of the HAR mark. More infor­ma­tion on the HAR mark. 

    Picture of the HAR Mark.
    The HAR Mark
  2. The HD 21.X and HD 22.X Har­mo­niza­tion Doc­u­ments pre­vi­ous­ly used for deter­min­ing com­pli­ance and apply­ing the CE Mark are being replaced by the EN 50525.X fam­i­ly of stan­dards start­ing on 2014-01-17. See the list.
  3. Wire and Cable prod­ucts with Dec­la­ra­tions of Con­for­mi­ty that refer to old­er ver­sions of the Low Volt­age Direc­tive, or that refer to HD doc­u­ments that have been super­seded are NO LONGER COMPLIANT.
  4. Wire and Cable prod­ucts used in “large-scale” machine tools and fixed instal­la­tions do not need to meet WEEE require­ments.
  5. Design­ers are not required to use CE Marked wire and cable prod­ucts in CE Marked Prod­ucts.

Need to know more? Check out this arti­cle!

Five things most machine builders do incorrectly

Five things that most machine builders fail to do. With a Sixth Bonus fail­ure!

The Top Five errors I see machine builders make on a depress­ing­ly reg­u­lar basis:

1) Poor or Absent Risk Assessment

Risk assess­ments are fun­da­men­tal to safe machine design and lia­bil­i­ty lim­i­ta­tion, and are required by law in the EU. They are a includ­ed in all of the mod­ern North Amer­i­can machin­ery safe­ty stan­dards as well.

Machine builders fre­quent­ly have trou­ble with the risk assess­ment process, usu­al­ly because they fail to under­stand the process or because they fail to devote enough resources to get­ting it done.

If risk assess­ment is built into your design process, it becomes the norm for how you do busi­ness. Time and resources will auto­mat­i­cal­ly be devot­ed to the process, and since it’s part of how you do things it will become rel­a­tive­ly pain­less. Where peo­ple go wrong is in mak­ing it a ‘big deal’ one-time event. Also get­ting it done ear­ly in the design process and iter­at­ed as the design pro­gress­es means that you have time to react to the find­ings, and you can com­plete any nec­es­sary changes at more cost-effec­tive points in the design and build process. The worst time to do risk assess­ment is at the point where the machine is on the shop floor ready to start pro­duc­tion. Costs for mod­i­fi­ca­tion are then expo­nen­tial­ly high­er than dur­ing design and con­struc­tion.

Poor­ly done, risk assess­ments become a lia­bil­i­ty defense lawyer’s worst night­mare and a plaintiff’s lawyer’s dream. Short­chang­ing the risk assess­ment process ensures that you will lose, either now or lat­er.

Fight this prob­lem by: learn­ing how to con­duct a risk assess­ment, using qual­i­ty risk assess­ment soft­ware tools, and build­ing risk assess­ment into your stan­dard design process/practice in your orga­ni­za­tion.

2) Failure to be Aware of Regulations & Use Design Standards

This one is a mys­tery to me.

Every mar­ket has prod­uct safe­ty leg­is­la­tion, sup­port­ed by reg­u­la­tions. Grant­ed, the scope and qual­i­ty of these reg­u­la­tions varies wide­ly, but if you want to sell a prod­uct in a mar­ket, it doesn’t take a lot of effort to find out what reg­u­la­tions may apply.

Design stan­dards have been in exis­tence for a long time. Most pur­chase orders, at least for cus­tom machin­ery, con­tain lists of stan­dards that the equip­ment is required to meet at Fac­to­ry Accep­tance Test­ing (FAT).

Why machine builders fail to grasp that using these stan­dards can actu­al­ly give them a com­pet­i­tive edge, as well as help­ing them to meet reg­u­la­to­ry require­ments, I don’t know. If you do, please either com­ment on this sto­ry or send me an email. I’d love to hear your thoughts on this!

Fight this prob­lem by: Doing some research. Under­stand the mar­ket envi­ron­ment in which you sell your prod­ucts. If you aren’t sure how to do this, use a con­sul­tant to assist you. Buy the stan­dards, espe­cial­ly if your client calls them out in their spec­i­fi­ca­tions. Read and apply them to your designs.

One great resource for infor­ma­tion on reg­u­la­to­ry envi­ron­ments and stan­dards appli­ca­tions is the IEEE Prod­uct Safe­ty Engi­neer­ing Soci­ety and the EMC-PSTC List­serv that they main­tain.

3) Fixed Guard Design

Fixed guard­ing design is dri­ven by at least two fac­tors, a) pre­vent­ing peo­ple from access­ing haz­ards, and b) allow­ing raw mate­ri­als and prod­ucts into and out of the machin­ery.

Design­ers fre­quent­ly go wrong by select­ing a fixed guard where a mov­able guard is nec­es­sary to per­mit fre­quent access (say more than once per shift). This is some­times done in an effort to avoid hav­ing to add inter­locks to the con­trol sys­tems. Fre­quent­ly the guard will be removed and replaced a cou­ple of times, and then the screws will be left off, and even­tu­al­ly the guard itself will be left off, leav­ing the user with an unguard­ed haz­ard.

The oth­er com­mon fault with fixed guards relates to the sec­ond fac­tor I men­tioned — get­ting raw mate­ri­als and prod­ucts in an out of the machine. There are lim­its on the size of open­ings that can be left in guards, depen­dent on the dis­tance from the open­ing to the haz­ards behind the guard and the size of the open­ing itself. Often the only fac­tor con­sid­ered is the size of the item that needs to enter or exit the machin­ery.

Both of these faults often occur because the guard­ing is not designed, but is allowed to hap­pen dur­ing machine build. The size and shape of the guards is then often dri­ven by con­ve­nience in fab­ri­ca­tion rather than by thought­ful design and appli­ca­tion of the min­i­mum code require­ments.

Fight this prob­lem by: Design­ing the guards on your prod­uct rather than allow­ing them to hap­pen, based on the out­come of the risk assess­ment and the lim­its defined in the stan­dards. Tables for guard open­ings and safe­ty dis­tances are avail­able in North Amer­i­can, EU and Inter­na­tion­al stan­dards.

4) Movable Guard Interlocking

Mov­able guards them­selves are usu­al­ly rea­son­ably well done. Note that I am not talk­ing about self adjust­ing guards like those found on a table saw for instance. I am talk­ing about guard doors, gates, and cov­ers.

The prob­lem usu­al­ly comes with the design of the inter­lock that is required to go with the mov­able guard. The first part of the prob­lem goes back to my #1 mis­take: Risk Assess­ment. No risk assess­ment means that you can­not rea­son­ably hope to get the reli­a­bil­i­ty require­ments right for the inter­lock­ing sys­tem. Next, there are small but sig­nif­i­cant dif­fer­ences in how the Cana­di­an, US, EU and Inter­na­tion­al stan­dards han­dle con­trol reli­a­bil­i­ty, and the biggest dif­fer­ences occur in the high­er reli­a­bil­i­ty clas­si­fi­ca­tions.

In the USA, the stan­dards speak of con­trol reli­able cir­cuits (see ANSI RIA R15.06–1999, 4.5.5). This require­ment is writ­ten in such a way that a sin­gle inter­lock­ing device, installed with dual chan­nel elec­tri­cal cir­cuits and suit­ably select­ed com­po­nents will meet the require­ments. No sin­gle ELECTRICAL com­po­nent fail­ure will lead to the loss of the safe­ty func­tion, but a sin­gle mechan­i­cal fault could.

In Cana­da, the machin­ery and robot­ics stan­dards speak of con­trol reli­able sys­tems (see CSA Z432, 8.2.5), not cir­cuits as in the US stan­dards. This require­ment is writ­ten in such a way that TWO electro­mechan­i­cal inter­lock­ing devices are required, one in each elec­tri­cal chan­nel of the inter­lock­ing sys­tem. This per­mits the sys­tem to detect mechan­i­cal fail­ures such as bro­ken or miss­ing keys, and if dif­fer­ent types of inter­lock­ing devices are cho­sen, may also per­mit detec­tion of efforts to bypass the inter­lock. Most sin­gle mechan­i­cal faults and elec­tri­cal faults will be detect­ed.

In the EU and Inter­na­tion­al­ly, con­trol reli­a­bil­i­ty is much more high­ly devel­oped. Here, the appli­ca­tion of ISO 13849, IEC 62061 or IEC 61508 have tak­en con­trol reli­a­bil­i­ty to high­er lev­els than any­thing seen to date in North Amer­i­ca. Under these stan­dards, the required Per­for­mance Lev­el (PLr) or Safe­ty Integri­ty Lev­el (SIL) must be known. This is based on the out­come of, you guessed it, the Risk Assess­ment. No risk assess­ment, or a poor risk assess­ment, dooms the design­er to like­ly fail­ure. Sig­nif­i­cant skill is required to han­dle the analy­sis and design of safe­ty relat­ed parts of con­trol sys­tems under these stan­dards.

Fight this prob­lem by: Get­ting the train­ing you need to prop­er­ly apply these stan­dards and then using them in your designs.

5) Safety Distances

Safe­ty dis­tances crop up any­where you don’t have a phys­i­cal bar­ri­er keep­ing the user away from the haz­ard. Whether its an open­ing in a fixed guard, a mov­able guard like a guard door or gate, or a pres­ence-sens­ing safe­guard­ing device like a light cur­tain, safe­ty dis­tances have to be con­sid­ered in the machine design. The eas­i­er it is for the user to come in con­tact with the haz­ard, the more safe­ty dis­tance mat­ters.

Stop­ping per­for­mance of the machin­ery must be test­ed to val­i­date the safe­ty dis­tances used. Fail­ure to get the safe­ty dis­tance right means that your guards will give your users a false sense of secu­ri­ty, and will expose them to injury. This will also expose your com­pa­ny to sig­nif­i­cant lia­bil­i­ty when some­one gets hurt, because they will. Its only a mat­ter of time.

Fight this prob­lem by: Test­ing safe­guard­ing devices.

6) Validation

OK, so this list should real­ly be SIX things. Just con­sid­er this to be a bonus for read­ing this far!

Designs, and par­tic­u­lar­ly safe­ty crit­i­cal designs, must be test­ed. Let me say it again:

Safe­ty Crit­i­cal Designs MUST Be Test­ed.

What­ev­er the­o­ry you are work­ing under, whether it’s North Amer­i­can, Euro­pean, Inter­na­tion­al or some­thing else, you can­not afford miss­ing the val­i­da­tion step. With­out val­i­da­tion you have no evi­dence that your sys­tem worked at all, let alone if it worked cor­rect­ly.

Fight this prob­lem by: TESTING YOUR DESIGNS.

A wise man once said: “If you think safe­ty is expen­sive, try hav­ing an acci­dent.” The gen­tle­man was involved in inves­ti­gat­ing the crash of a Siko­rsky S-92 heli­copter off the coast of New­found­land. 17 peo­ple died as a result of the fail­ure of two tita­ni­um studs that held an oil fil­ter onto the main gear­box, and the fact that the heli­copter failed the ‘1/2-hour gear­box run-dry test’ that is required for all new heli­copter designs. This was a clear case of fail­ure in the risk assess­ment process com­pli­cat­ed by fail­ure in the test process.