WEBVTT Kind: captions Language: en 00:00:35.067 --> 00:00:41.158 [Music] Every single day electricians in Denmark work on electrical installations including switchboards. 00:00:45.983 --> 00:00:51.175 They often work on live installations  or in the vicinity of live installations with   00:00:51.175 --> 00:00:57.860 a risk of electric shock and injuries caused  by short circuits or arcs. 00:01:01.881 --> 00:01:09.724 Statistical data from the Danish Safety Technology Authority show that the number of accidents resulting from work   00:01:09.724 --> 00:01:15.814 on switchboards has slightly been decreasing  over the last years. However these numbers also   00:01:15.814 --> 00:01:20.752 indicate that there is a slight increase when  we discuss the category of accidents where the   00:01:20.752 --> 00:01:29.085 live working regulations were not observed. The  consequences are often severe due to the fact   00:01:29.085 --> 00:01:36.410 that protective gear was never used during these  types of accidents.Burns on hands, arms, shoulders,   00:01:36.410 --> 00:01:47.120 neck and face. Unfortunately the descriptions of  such accidents are often identical. Melted copper   00:01:47.120 --> 00:01:53.210 particles on a pair of glasses often testify  that the electrician's eyes were spared as he   00:01:53.210 --> 00:02:05.000 triggered the short circuit with the uninsulated  jaws of a pair of long nose pliers. 00:02:05.000 --> 00:02:09.980 they called from the office in shipping and said that the  lights were out. I hurried out the door 00:02:09.980 --> 00:02:15.590 and when I reached the switchboard I could see the fuse had blown. There was a little dirt on the contact   00:02:15.590 --> 00:02:21.470 in the bottom of the fuse holder which I removed  with the screwdriver. I admit it was thoughtless. 00:02:21.470 --> 00:02:29.210 There was a sizzling sound then a large  bang and the next thing I heard was the   00:02:29.210 --> 00:02:33.230 office manager who yelled if I  could hear anything. He told me   00:02:33.230 --> 00:02:37.280 that I was black and burnt in the face  so he wanted to take me to the doctor. 00:02:37.280 --> 00:02:46.220 The doctor who saw me rushed me off to hospital  right away as he said there was something in my   00:02:46.220 --> 00:02:52.010 eyes, With sirens and police escort I was  rushed to the hospital and I realized that   00:02:52.010 --> 00:02:57.530 my sight was in danger. I spent a long time in  the operating room where the doctors removed   00:02:57.530 --> 00:03:03.470 copper from my corneas. The doctors never  promised anything but already the next day   00:03:03.470 --> 00:03:13.250 I was recovering and my sight is now slowly  getting back to normal. I was lucky. 00:03:24.465 --> 00:03:30.300 Accidents with safety tools without proper  insulation occur over and over, the statistics show.   00:03:31.209 --> 00:03:37.940 In this next very typical accident the electrician  did not use proper safety gear such as gloves and   00:03:37.940 --> 00:03:46.100 glasses. Among the most common causes of accidents  are also insufficient screening materials.  00:03:46.100 --> 00:03:52.010 In this case the electrician was dismounting some  temporary construction sites switchboards from the   00:03:52.010 --> 00:03:58.550 main switchboard when he dropped his uninsulated  spanner at the main rail. This short-circuiting   00:03:58.550 --> 00:04:05.240 accident whereby he was seriously burned could  have been avoided had he only used safety tools   00:04:05.240 --> 00:04:12.350 and made sure the proper screening material was  in place. Quite a few accidents occurred during   00:04:12.350 --> 00:04:19.310 metering and troubleshooting on live switchboards.  These pictures are from an accident where the   00:04:19.310 --> 00:04:25.730 electrician used a measuring instrument with  a maximum capacity of 700 volts AC. But there   00:04:25.730 --> 00:04:32.780 was 900 volts AC on the site. The result was  a short-circuit and an arc which caused burns   00:04:32.780 --> 00:04:39.830 on the electrician's face and hands. Pressure  and a lack of common sense may have disastrous   00:04:39.830 --> 00:04:46.160 consequences. In a case where the electrician was  about to install an emergency generator at a farm   00:04:46.160 --> 00:04:51.920 he felt convinced that there was no voltage on  the system. The electrician never carried out a   00:04:51.920 --> 00:04:59.660 control measurement and it did cost him his life.  The consequences are rarely that severe but the   00:04:59.660 --> 00:05:07.280 physical consequences of an electric shock are  actually quite critical. When professionals are   00:05:07.280 --> 00:05:11.930 involved in accidents they often know what  went wrong. However sometimes they cannot   00:05:11.930 --> 00:05:17.930 react appropriately or do not understand the  consequences. We have to be careful when people   00:05:17.930 --> 00:05:23.480 have burns. We do not want to miss the internal  burn injuries or effects of the shock. Because   00:05:23.480 --> 00:05:28.580 often the visible changes that occur after an  electric shock are quite limited. There may be   00:05:28.580 --> 00:05:34.430 a tiny entry hole and a small exit hole and if  you're not paying attention you may not discover   00:05:34.430 --> 00:05:41.630 the internal injuries even if we cut the patient  open. Often the skin seems fine but we have to open   00:05:41.630 --> 00:05:47.690 up to large areas of the body or on arms or legs  to relieve the pressure underneath the muscle to   00:05:47.690 --> 00:05:53.450 make sure the blood supply continues. So the best  case scenario is that you end up with scars from   00:05:53.450 --> 00:05:58.940 the cuts. The worst case scenario is that you  lose parts of the skin, an entire hand or foot.   00:05:58.940 --> 00:06:05.030 But of course we do everything possible to let  the patient keep as much as possible. However the   00:06:05.030 --> 00:06:10.580 damages we see are often severe. The muscle may  simply have been boiled due to the generation   00:06:10.580 --> 00:06:19.730 of heat. The Danish Safety Technology Authority  recommends consulting a doctor in case of strong   00:06:19.730 --> 00:06:26.960 electric shock. In the Danish heavy current  regulations section 6 electrical installations   00:06:26.960 --> 00:06:35.180 applicable from June 1st 2001 and with binding  effect from January 1st 2003 it is stated that   00:06:35.180 --> 00:06:41.000 in general it is permitted to work on live or  on dead switchboards as long as the rules of   00:06:41.000 --> 00:06:46.970 the heavy current regulations are observed. The  rules also include work on installations and   00:06:46.970 --> 00:06:53.510 machines. In principle there are three different  methods. Installations that are neither live nor   00:06:53.510 --> 00:07:01.370 charged or installations where precautions have  been made for electrical danger or installations   00:07:01.370 --> 00:07:08.060 where the electrician is in contact with live  parts either by his tools equipment or parts of   00:07:08.060 --> 00:07:15.110 the body. Or finally work can be performed around  voltage areas where the electrician with his tools   00:07:15.110 --> 00:07:25.700 equipment or parts of his body gets into the  vicinity zone. It applies to all three methods   00:07:25.700 --> 00:07:32.159 that precautions must be taken for electrical  shock. The effects of short circuits and arcs. 00:07:39.968 --> 00:07:44.000 Here we have chosen to work on a dead  installation and when we do that we have   00:07:44.000 --> 00:07:49.070 to make sure that everything is disconnected  and in this case we will use the disconnector.   00:07:49.070 --> 00:07:54.590 I turn the handle down to zero and to  make sure that no one comes along and says   00:07:54.590 --> 00:08:00.950 okay this one is clear we'll start up production  I lock the disk connector with my padlock. And as   00:08:00.950 --> 00:08:05.300 an extra safety measure I hang up the sign  so that everyone can actually see that this   00:08:05.300 --> 00:08:11.845 location is disconnected for a reason. So now noone can accidentally switch the disconnector on. 00:08:15.446 --> 00:08:21.500 Another way to ensure that the installation stays  disconnected is to remove the fuse links. Before I   00:08:21.500 --> 00:08:26.900 do that I disconnect the supply using the disk  connector. Now I prepare to open the door with   00:08:26.900 --> 00:08:31.910 my screwdriver and before opening the door I  want to put on my safety glasses due to the   00:08:31.910 --> 00:08:38.720 fact that removal of fuse links may cause an  arc. I put on my insulated fuse remover which   00:08:38.720 --> 00:08:43.490 provides a high degree of protection and  a good grip. It is important to remove the   00:08:43.490 --> 00:08:48.830 fuse link in one motion. Regardless of whether  you choose this method of removing fuse links   00:08:48.830 --> 00:08:53.930 or a different method such as removing wires  or bus bars you always have to make sure that   00:08:53.930 --> 00:09:00.000 this sign is visible to avoid that someone  tries to activate the installation. 00:09:03.147 --> 00:09:07.880 Now we  have to make sure that the switchboard is  not live. We use this instrument to check   00:09:07.880 --> 00:09:13.550 the voltage level. Before using the instrument  on the switchboard I have of course checked   00:09:13.550 --> 00:09:25.130 that it works. We want to make sure that the  installation is dead and I choose to use gloves   00:09:25.130 --> 00:09:30.950 and glasses to reduce the risk of touching  life parts and to avoid injuries by arcs. 00:09:36.580 --> 00:09:42.980 I can see that the installation is  not live. When I've done that I   00:09:42.980 --> 00:09:47.660 take off my gloves and use my voltage  indicator again to check that there is   00:09:47.660 --> 00:09:51.890 no voltage and check that there is  no life external control circuits. 00:09:51.890 --> 00:10:04.070 That is not the case here. Unfortunately a lot of  electricians still use the old voltage indicator   00:10:04.070 --> 00:10:10.460 which I have here in my pocket. It's not very  appropriate to use. The reason is that it has   00:10:10.460 --> 00:10:15.830 this long metal tip instead of plastic and  the long tip increases the risk of creating   00:10:15.830 --> 00:10:21.830 a short-circuit and thus an arc. So I simply  avoid using this one on the switchboard and   00:10:21.830 --> 00:10:29.690 put it back in my pocket. It is not appropriate to  use here. Sometimes it may be necessary to work on   00:10:29.690 --> 00:10:36.500 live switchboards. In that case the electrician  must observe a set of safety rules. In Denmark   00:10:36.500 --> 00:10:47.780 commonly referred to as L-AUS. Before working  on the live switchboard we want to make sure   00:10:47.780 --> 00:10:56.300 that our protective gear is secure. The first  thing I do is remove my rings and my watch. 00:10:56.300 --> 00:11:01.850 When I've done that I want to make sure that I wear the  right clothes. The right clothes could be working   00:11:01.850 --> 00:11:06.110 clothes such as mine which are particularly  suitable for high temperatures and are made   00:11:06.110 --> 00:11:11.630 of fire resistant material. Of course it is also  important that you do not wear synthetic materials   00:11:11.630 --> 00:11:17.390 underneath as they may burn or melt easily. I put  on my helmet and now you could select either a   00:11:17.390 --> 00:11:26.060 face visor or glasses. In this case I have chosen  glasses because I like them better. I also want   00:11:26.060 --> 00:11:31.400 to wear gloves and first I put on my protective  gloves- my rubber gloves which protect me from   00:11:31.400 --> 00:11:37.100 electrical shock. And on top of those I put a  different pair of protective gloves to avoid   00:11:37.100 --> 00:11:45.650 damage to my rubber gloves. Now some would say  that it is a lot of trouble with all this safety   00:11:45.650 --> 00:11:50.810 gear but remember that if you work without  it it is your life that we're talking about. 00:11:55.572 --> 00:12:01.520 We also want to use an insulating mat - a stepping  mat that we can stand on. And it is important   00:12:01.520 --> 00:12:06.950 that you choose a sufficiently large mat of  not less than one square meter. It has to be   00:12:06.950 --> 00:12:17.210 skid-proof on both sides and at least two and a  half millimeters thick. Now I'm ready to work on   00:12:17.210 --> 00:12:28.610 a live installation when replacing an RCD such  as this one. Under voltage we have to make sure   00:12:28.610 --> 00:12:33.530 that there is no possible contact to any of  the other voltage potentials present in the   00:12:33.530 --> 00:12:39.650 switchboard. We have to cover everything and make  sure that only one potential is available at a   00:12:39.650 --> 00:12:45.440 time. We want to use this type of cloth which is  an insulating type of material with a thickness   00:12:45.440 --> 00:12:51.800 no less than 0.5 millimeters and of course  we now have to fit the material to suit the   00:12:51.800 --> 00:12:57.320 purpose. We want to secure the material onto  the switchboard and a good way to do that is   00:12:57.320 --> 00:13:05.210 to use these insulating clips. As a supplement  you can also use tape. I have to make sure   00:13:05.210 --> 00:13:11.840 that the wire ends which I now disconnect from  the RCD are not dangerous.They are not 00:13:11.840 --> 00:13:17.270 once I put them into this shroud that I have here.  The shroud has a slight barb which prevents   00:13:30.200 --> 00:13:35.480 and this first part prevents us from accessing  live parts in the back and I also have to make   00:13:35.480 --> 00:13:42.140 sure that tools and other parts do not fall down  in the switchboard. But we are far from finished 00:13:46.530 --> 00:13:52.920 because we also want to insulate other parts such  as here on the switchboard side where we want to   00:13:52.920 --> 00:14:03.840 avoid that a face conductor or a neutral wire hits  the frame of the switchboard. We want to secure   00:14:03.840 --> 00:14:12.150 against the cable area here. But there is also a risk  that one of our phase conductors which is loose   00:14:12.150 --> 00:14:18.210 here may hit the DIN rail in the switchboard.  That would result in a dangerous situation  - 00:14:18.210 --> 00:14:29.280 a short-circuit. So we want to cover the DIN rail  also. We are now at the point where we only need to   00:14:29.280 --> 00:14:35.520 cover the area between the multiple switch unit  here and the RCD. So we'll just put a piece of   00:14:35.520 --> 00:14:38.370 screening material here as well. 00:14:50.258 --> 00:14:54.000 A lot of accidents happen because of the inappropriate choice of tool.   00:14:54.000 --> 00:15:00.259 we have chosen a screwdriver which is marked with  two triangles on top of each other and 1000 volts.   00:15:00.876 --> 00:15:07.530 So this is a suitable screwdriver. A different  screwdriver which is also marked with 1000 volts.   00:15:07.530 --> 00:15:13.950 And in this case a bell would also be suitable  if it wasn't damaged. We can see that there is a   00:15:13.950 --> 00:15:20.520 defect in the insulation layer. So we'll put this  one away, it is not suitable. We also need a pair   00:15:20.520 --> 00:15:25.890 of long nose pliers to hold the wires inside the  switchboard when we apply the shrouds. This one   00:15:25.890 --> 00:15:32.160 is marked with two triangles and 1000 volts and is  completely made of insulating material which makes   00:15:32.160 --> 00:15:40.620 this a suitable pair of pliers. Now this pair of  long nose pliers is also marked with 1000 volts so   00:15:40.620 --> 00:15:46.860 why not use it. It has a long piece of uninsulated  material here and when in a switchboard it may   00:15:46.860 --> 00:15:53.640 cause a short circuit so it does not belong  here. Here is a pair of side cutting pliers.   00:15:53.640 --> 00:15:59.120 The side cutting pliers are also made of insulating  material and are marked with two triangles and    00:15:59.120 --> 00:16:04.760 1000 volts. And we can see here that the jaws are  also made of insulating material which makes it   00:16:04.760 --> 00:16:17.540 suitable for use on the switchboard. We now want to  start replacing the RCD. We will start by loosening   00:16:17.540 --> 00:16:23.630 this wire. Everything is already properly covered  and only one voltage potential is available at   00:16:23.630 --> 00:16:34.160 a time and we have also covered other live parts  and conductors to the RCD. I'll take my screwdriver   00:16:34.160 --> 00:16:43.310 and my pair of long nose pliers and prepare to  loosen the wire. But now I see that I have a cable   00:16:43.310 --> 00:16:51.508 tie up here and I have to cut it to be able  to loosen the wires. I'll just do that. 00:17:04.865 --> 00:17:14.920 Now I can loosen the wire. I take my pair of  long nose pliers to hold the wire so that it   00:17:14.920 --> 00:17:20.050 doesn't touch any other live parts. They  have been covered but I'll use the pair   00:17:20.050 --> 00:17:28.060 of long nose pliers to hold the wire. I can  now pull out the wire and mount a shroud on   00:17:28.060 --> 00:17:39.070 the wire. It has a little bit of resistance  due to the barb on the shroud. And by putting   00:17:39.070 --> 00:17:43.570 the wire well into the shroud the barb  has a good hold and the shroud does not   00:17:43.570 --> 00:17:45.596 easily come off. 00:17:48.358 --> 00:17:52.386 I'll move on and remove  the tape. Make a new cover so I can take   00:17:52.386 --> 00:17:58.618 the next wire. And every single time I have  to make a new cover against the live parts. 00:17:58.618 --> 00:18:06.190 It is a slow process but it is necessary  and always remember that this is a risk   00:18:06.190 --> 00:18:13.120 to your life so there are no easy shortcuts.    00:18:16.057 --> 00:18:23.854 When using your measuring instrument it is important to perform a risk assessment to be  able to foresee the dangers and risks that   00:18:23.854 --> 00:18:29.530 may arise. If you measure voltage over a long  period of time or if you want to determine the   00:18:29.530 --> 00:18:34.720 existence of a short circuit it is important  that the voltage probe is properly attached.   00:18:34.720 --> 00:18:41.560 Actually it is now possible to buy probes  particularly for this purpose. Here is a probe   00:18:41.560 --> 00:18:50.380 particularly suitable for use on a bolt. As we  can see here we can tighten the voltage probe,  00:18:50.380 --> 00:19:02.830 remove the handle, mount a wire and we can now do  the measuring. As you can see it fits tightly here. 00:19:08.147 --> 00:19:15.460 I'll remove the probe again and try to  find a different type of probe. Here is   00:19:15.460 --> 00:19:18.550 one where we can see that there's  only a tiny area of metal in the   00:19:18.550 --> 00:19:26.875 bottom. Everything else is of plastic. This  way we can eliminate the risk of causing a   00:19:26.875 --> 00:19:36.000 short-circuit. I will try to connect our  measuring instrument to the switchboard. 00:19:37.500 --> 00:19:42.617 We can see that I can put in the  probes to ensure a good and safe metering.