Polarity

English: Types of electric current
Types of electric current (Photo credit: Wikipedia)
4 diodes bridge rectifier
4 diodes bridge rectifier (Photo credit: Wikipedia)

If you are an electrician, technician or electrical engineer you will know all about polarity. For those who don’t it is a reference to which way round a circuit is connected to its supply or the way the supply is connected to the circuit or appliance. Most people have an understanding about direct current and alternating current. Typically the current supplied from a battery (of cells) flows in the one direction only whereas the electrical supply to a house (and other places of course) is alternating and essentially flows in both directions, though that is a bit of a theoretical misnomer. Certain things will not work if the current is supplied in the wrong direction, one of those things being diodes. In fact diodes are installed in circuits to ensure current can only flow in the one direction. LED lights or light-emitting diodes are in fact specially constructed diodes which emit photons when a current flows through the device. If the current is presented the wrong way round (wrong polarity) they will not light up. However they can be used if supplied by an alternating current if a bridge rectifier is used.  A bridge rectifier is a device constructed with diodes connected in a special way which forces the current to flow in one direction. Here ends the brief electrical lesson but I write it in order to explain my post.
I had installed an LED strip light (resembling a fluorescent lamp) in a house in summer. The lady called me to explain that it had ceased working so naturally I went to investigate. I discovered that the lamp (tube) was indeed at fault as the supply was intact. The supply to the lamp is at one end only, unlike the fluorescent equivalent which is supplied at both ends. That obviously means the tube itself has to be installed the right way round so that the supply can connect to it. Now then, the lighting unit manufacturer has installed the correct colour-coded internal wiring, brown and blue which are live and neutral respectively together with a small fuse. The lamp connector therefore has one brown and one blue conductor connected to it. The end of the tube lamp which plugs into it is marked L and N denoting which terminal connects to each when the lamp is inserted. However when the lamp is inserted so that it shines down into the room the connections end up the wrong way round! That would mean that the lamp supply is the wrong polarity or the wrong way round but in fact it didn’t matter in this case for the lamp worked whichever way it was inserted. That could only mean that a bridge rectifier was in circuit within the lamp’s electronic components. Why then the need to mark the terminals on the lamp L and N? I can only assume it is for information when connecting it to a direct current supply but even that wouldn’t be correct as for a DC supply they would have been marked with the symbols + and -. So why mark the lamp in the first place? I had the lamp replaced under guarantee and it worked just as the other had done. If only the manufacturer had indicated these things in their literature, it would have saved me the time and effort trying to figure it out for myself. The lamp was replaced under guarantee but my time had to be paid for though.

Shirley Anne

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The run around day

Don’t you just love Mondays? Monday started showery though it was quite mild with little in the way of wind. My scheduled electrical job was to check for an intermittent fault on a distribution board in an out-house (a built-on extension to the main building) and to replace two floodlights on the outside walls of that extension. It was dry when I arrived but soon after opening my toolbox it began to rain. However, because the forecast was for showers I expected the rain to stop after a few minutes, and it did but that was the pattern for the next hour or so. By noon the sun was ‘cracking the flags (paving stones)’ as we say but long before then I had finished the work. The reason for the distribution panel’s RCD tripping intermittently was due to one of the old floodlights which had become detached from the wall. It was hanging by the electrical cable leaving the connection box exposed to the elements. I removed it and fitted the new one which had been supplied by the customer. Her son had purchased two replacement tungsten-halogen fittings and had given them to her. I left setting it up until after the second floodlight had been installed. I set the controls on the first floodlight and it worked perfectly but when I did the same to the second light it wouldn’t switch off. The lady and I waited for quite some time for the light to ‘settle down’ as sometimes they can be quite temperamental when first switched on. This unit just didn’t want to know! The lady asked if I could simply buy a new one instead. She opted for me to purchase an LED version so I drove off to purchase one. The picture shows the same model.floodlightI was away from the house for almost a half-hour and on my return I saw that the floodlight had finally switched itself off! As I had set it up for automatic night-time switching the lady asked if I could leave it and see if indeed it was now going to behave itself. She sent me a text message later to let me know everything worked fine. I didn’t bother returning the newly purchased light as either she might find the light is faulty or someone else might want one. With the connection box included the price was under £25 so it will remain as van stock for the time being. I drove off to view another job and whilst doing so a lady I had been to see the previous week regarding replacing her outside wall lantern called to let me know she had purchased the replacement. It was in the next township but as the weather had now turned out for the better I took the opportunity to go and replace it for her. By now it was one-thirty and beyond my lunchtime. I didn’t get lunch until almost two-thirty. It happens quite often. My little run about paid well anyway so I was happy.

Shirley Anne

Two different days

On Friday I had a little work scheduled to do in the next little township, Formby, just a few miles away from home. I thought the work would take two or maybe three hours and I would then have the rest of the day to myself but as sometimes happens it didn’t work out that way. Replacing light fittings and a few power outlets unearthed a can of worms. There were incorrectly wired lights and power outlets which had to be tackled before I could do the work I had been asked to do. The couple with their twenty year-old son had recently moved in to the property and had not really had the chance to settle in because of the work that had to be done first. That is a common thing though in acquiring a new home. So my work took me until four in the afternoon to complete not only because of the problems but also because they had asked me to do other work too. One job I refused to do concerned the garage and greenhouse wiring installation. The lighting circuits especially were in a potentially dangerous condition and there was a problem with the power circuits too. I did do some work there but only to make it safer than it was. It would be too large a project for me to consider to rewire the garage and the greenhouse now that I have made the decision to cut back on my electrical work. I suggested they seek the services of a younger electrician! Anyway they were pleased with what I had done and they will call me again they say when there are other small jobs to do. Saturday was a completely different day. I made an inventory of my electrical van stock and decided to visit the supplier to renew my stock of switches, power outlets, and boxes. Whilst there I purchased another LED floodlight for our rear garden. floodlightOne of the five had become faulty so I plan to change it with the one that overlooks the Plot I have been working in recently just to maintain the symmetry on the rear wall of the house. The new one will be positioned further along the side wall from where the supply is now. I will do that work in the next week or so when I feel like doing it. I also asked if they had sourced the part-night photo cell I had asked of them a week or so ago but they were having the same difficulty as I’d had in obtaining one. I left there to visit the other supplier I had also asked and they gave me a more positive answer. It seems that these photo cells are usually supplied in large quantities but to supply just one doesn’t interest them. This supplier though tells me that they can certainly supply one and will inform me in a day or so when they have one for me. At least I know I will finally get one. I drove home, stopping on the way to buy a couple of grocery items. The rest of the day would be spent relaxing.

Shirley Anne

Talk about modern technology

Readers of my previous post my have noticed a related article at the bottom of the post. I am never sure if any of those related posts will be read but I place them there for anyone who might be interested. I few weeks ago now we had our street lamp-post replaced after it had been damaged by a delivery driver. There seem to be thousands of delivery drivers these days with the advent of on-line shopping. The street lamp is fitted with an LED cluster of lamps which are very economical to run compared with any of their predecessors.

OLYMPUS DIGITAL CAMERA

We perhaps don’t notice such things as we go about our daily lives and maybe we don’t need to but there are plans afoot to install ‘intelligent’ lamp-posts which not only provide light but will also be able to provide cctv. and even WiFi. From a lamp-post? Have a read of this article….  http://www.latestarticlesonline.com/worried-connected-street-lights/ . You will have to copy and paste address in new tab or click on the middle of the three articles under my previous post.

Shirley Anne

So it rained

I was supposed to be driving off to the job I had scheduled on Monday morning but it had begun to rain and the forecast was for rain throughout the day. So I stayed at home. The work was to be done outdoors so it would have been difficult if not hazardous to do it especially as it would all be done up a ladder! I called my customer about 70 minutes before my expected arrival but could only leave a message as apparently she was unavailable according to her messaging service. landline-phoneI called back several times during the following hour and a half then gave up. She finally called me wondering why I hadn’t turned up. I explained with the same information you’ve just read. She checked her messages and discovered nothing had been recorded. What was going on? Anyway we made arrangements for me to visit the following day when the weather would be better. I was hoping the lamp-post would be delivered whilst I was at home. E is home much of the time but I couldn’t rely on her being available to sign for the delivery. The problem was not knowing on which day it would arrive but as luck would have it the post was delivered mid-morning. However I was shall we say, ‘indisposed’ and E must have heard the doorbell ring and she came downstairs to answer the door. She had been at the top of the house in her ‘workshop’. I confessed to having not heard the doorbell and had the delivery men come a couple of minutes earlier or later I would have been there to accept the delivery as I was actually on the same floor. That is very typical of many folk’s experiences I’m sure, we wait in for something to arrive and then just for a moment we are indisposed and it arrives! I have a feeling it happens by design! I took the three packages downstairs into the cellar where I began to remove the enormous amount of corrugated cardboard and bubble-wrap surrounding the three main items, the heavy base unit, the pole and accessories and the lamp itself.  I discovered they had included a light-sensing economy lamp (fluorescent) in the package. They are designed to switch on from dusk till dawn and of course will remain on throughout the night. It will do for the moment but I am still trying to obtain a part-night sensor/controller and if I do I will replace the lamp with an LED one.

English: Construction and function of a light ...
Construction and function of a light emitting diode (LED) (Photo credit: Wikipedia)

At least I won’t have to wait until I obtain a sensor for the light to work. Having unpacked the parts I now know what has to be done. My first task will be to cut off the excess cable near to where the post will be and set it in position with more concrete so that it will emerge beneath the pole when it is fixed to the base. The pole is designed to be fixed using  four ‘rawlbolts’. All I need now is for some dry weather……….

Shirley Anne

I wonder

Re-Experienced
(Photo credit: Wikipedia)

I experienced one of those unusual days, well morning on Wednesday, the sort of day where things don’t go to plan as easily as they might. First port of call was to a regular customer’s house a mile or so away to check out a faulty floodlight. A separate motion detector turned out not to be faulty and it was only the lamp inside the floodlight fitting which required replacing. However the lady wanted to have me install an LED floodlight instead of the halogen one that was there. I had replaced another halogen light at the side of the house some months ago with an LED version but at that time she didn’t want this one changing. Simple enough and straightforward to replace it now. I invited her along to purchase a new fitting and whilst at the counter I received a call from someone living ten miles or more distant. I asked if I could call them back. We purchased the new fitting and off we went. As floodlights go this was very sturdy and well designed but when it came to installing it wasn’t so easy to fit. The main problem was its weight. A bracket had to be removed so it could be fixed to the wall. Removing it wasn’t so easy but fixing it to the wall was. I then had to reattach the light to the bracket and that’s when the problems really started. The designers could have made the task far easier with a little thought. It’s as though they don’t understand that usually their floodlights will be installed high on an outside wall using a ladder and as such is difficult enough without it being a poor design too. Anyway I got the job done like I usually do and called the guy who had phoned earlier. He had a faulty control unit which supplied his immersion heater, so he said.

Resistance heating element
Resistance heating element (Photo credit: Wikipedia)

On my arrival I checked the supply was getting to the control unit and at first it didn’t seem to be but then I discovered it was after I moved the timer a little. The override switch which gives an hour’s boost during the daytime was also working as it should. The controller is one of the type for use when the electricity supply to the house is delivered at a lower levy overnight, what they used to call an ‘off-peak’ rate. I set the timer and then checked the immersion heater itself to ensure that the replacement unit had been installed properly by the plumber I was informed had fitted it. I removed the cover and noticed it was burnt in one spot. I thought that was odd because new heaters are supplied with new covering lids and indeed on closer inspection the heater didn’t look as if it had been replaced where it was screwed into the water tank. A new thermostat had been fitted however. One of the element terminals, the neutral connection was badly burned and the cable attached to it was likewise burned, in fact as I moved it I found it wasn’t connected at all. It was apparent that a plumber had not been involved at all but the guy himself had replaced the thermostat thinking that was the heating element and assuming he had solved the problem. I said nothing to embarrass him but told him he would have to get another plumber to replace the whole unit and then all should be well. I prepared the cable for re-connection and left it safe for whoever would install the heater. Until fairly recently I would have done the plumbing work myself but I have cut back on the type of work I am now prepared to do. I wonder why some people think they can ‘pull the wool’ over the eyes of a professional and get away with them not noticing? In my working life I have experienced this often, people denying they had anything to do with the problems they give to me to fix. This guy would have saved himself a lot of money had he called in the professionals in the first place.

Shirley Anne

Unbelievable

English: Fluorescent lamp
Fluorescent lamp (Photo credit: Wikipedia)

What a day! Over the years I have come across many different problems in my line of work and I often say to myself that it never ceases to amaze me when some new problem arises. It isn’t the problems themselves but more the fact that some of them wouldn’t be problems if manufacturers and designers of equipment realised they were building them into their goods. Often no feedback mechanism exists to help in eliminating problems and to improve designs. I had two small jobs to do on Thursday morning and I expected to have them both completed within two hours but unfortunately I was away from home for more than six! A lady had bought a new light fitting and I was to install it. The existing lighting, recessed downlights did not give enough light though they were halogen lamps. The reason for that was most of them had been changed to LED lamps but of a far lower equivalent rating to be bright enough. The easy answer would have been to put higher capacity lamps in but she and her husband had decided to purchase what they thought was a twin-tube LED fitting instead. Actually they had bought a modern fluorescent lamp fitting and two LED tube lamps to fit in it. Now I have seen fittings of this type before, they look like an ordinary fluorescent fitting but are different. I gave it no thought and proceeded to install it but first I had to locate the supply to the existing recessed lights and divert it to the new fitting. That was a job in itself for the supply could have been anywhere in the false ceiling but I located it quicker than I had thought I would. It took some time to install the new light fitting and when I had finally succeeded I discovered it wouldn’t work. I checked the supply and all was well so the problem lay in the light itself but there was nothing evidently wrong. We contacted the supplier from where she had purchased it and I explained the problem. They allowed me to bring back the internal part of the fitting and have it replaced rather than having to remove the whole unit from the ceiling. I drove there with the lady as my passenger and the salesman was unable to reason why we were having problems. The manager came to the desk and we discussed things. It turns out that they had sold the lady a fluorescent fitting with LED lamps in error. It could only work with fluorescent lamps and not LED lamps. That explained a lot for I had been under the impression that its internal components were LED ‘drivers’ but in fact they were choke units, the devices normally found in a fluorescent fitting. Ironically the fitting could have been modified to use LED lamps but that would have meant cutting the internal wiring and partly rewiring it, something you wouldn’t do with a new fitting. The supplier admitted their error and offered the lady a larger fitting for the same price and she accepted it. It was an LED lighting unit that had the LEDs built into it, no separate lamps to install. It actually looks much the same as the fluorescent fitting in the picture above. We drove back to her house and I installed it. However, although the light worked first time with no problems when it came to fixing the diffuser it was a nightmare! It had been manufactured to hold the diffuser in place with 16 or so metal clips which were almost impossible to fit into place and even when I had managed to do that it was extremely difficult to clamp the diffuser in place using them. In the above picture you can see two of the four clamps of a similar nature holding the diffuser in place. A much simpler way of fixing the diffuser would have saved so much time and frustration if it had been designed that way. I took the rest of the first fitting back to the supplier as I’d promised and by chance I spoke with the manager again who confessed that he had installed the same LED fitting at home and had exactly the same problems in fixing the diffuser. The second job I had been to replace a small lamp holder and it took me a mere ten minutes by comparison! I didn’t get back home until mid-afternoon. Some days you wished you’d never gotten out of bed.

Shirley Anne

Behave yourself

TN-S-earthing de
TN-S-earthing de (Photo credit: Wikipedia)

I was expecting to have a second day all to myself again on Thursday for I had spent Wednesday entirely at home and it looked like Thursday was going to be the same. At 9.45 I got a call on my mobile phone from a guy who wanted me to do some electrical jobs for him on the other side of town. I was there just after 10 o’clock and was invited in. He was expecting me to give him an estimate for the work that at this time he was asking to be done for he told me there was plenty more to do at a later date. The work I was to do however would be difficult to assess until work began so he suggested paying me for a half-day’s work instead. I explained that if I could do the work in less time I wouldn’t charge for the half day. It often happens that unforeseen problems occur and can therefore lengthen the time it takes to do the work. I agreed though that I wouldn’t charge more than a half-day’s pay should that happen. I began the work of removing five surface-mounted dimmer switches and replacing them with new ones flush-mounted, which meant digging out the wall to accommodate new recessed boxes. I discovered that two of the lights (circuits) had been incorrectly wired in that the earthing conductor was being used to carry current, something it is not designed to do. In a standard cable the earthing conductor isn’t insulated as the current carrying conductors are. Its only protection is a mechanical one provided by the overall PVC covering around all the conductors. That PVC isn’t the insulation. When earthing conductors are exposed where they are being connected they are provided with a green and yellow PVC sleeve by the electrician and that is all that is required. In this incidence those earthing conductors had a coloured sleeve and were being used to carry the current. This is totally against all regulations. I now had the problem of maintaining the supply to the lights affected. One had to be abandoned and fortunately that particular light (on the ceiling) wasn’t generally being used anyway. The second light (on a wall) could be maintained by re-feeding its live conductor from a switch nearby which was actually one of the two switches controlling it (two-way control). For that to happen though meant that it’s accompanying switch across the room would have to be the one to which the live supply was connected or the light would have to be disconnected. I was in luck and therefore I channelled out the wall to install the cable. I could have rewired both lights but the customer didn’t want the upheaval it would cause or the price it would cost for it would have taken a few hours to do. They opted for the simpler version instead. The second part of the job was to explore the reason a large outdoor floodlight wasn’t working and why, when the switch was set it tripped-out the main supply. That took a little time but I finally located the fault inside the floodlight itself where one of the lamp connections had burned beyond repair. The lamp itself showed the effects of excess heat, the lamp being as it was 750 watts! Most of that power would be in the form of heat and not light, something like in the ratio of 90% heat to 10% light. This is why it is better to use LED lighting if possible for the ratio is better and something in the order of 90-95% light and 5-10% heat and means a much lower rating can be used whist maintaining the same light level. Anyway the floodlight will have to be replaced and I left that with the customer who said he would ‘shop around’. I gave him advice on that one. I had been there for five hours and was about to leave when he asked me to look upstairs to view his loft conversion proposal which will need the services of an electrician if and when it happens.

Oh, Mabel Behave
Oh, Mabel Behave (Photo credit: Wikipedia)

The loft had already been converted by the previous owner but it will have to be redone for the floor joists (timbers) are too small for their intended use and could be dangerous if the loft continues in use as it stands. Unfortunately as I explained to the guy, I doubt I will be taking on the work for it amounts to the same as doing a complete rewire. I would be at the beck and call of other trades persons too and I have had enough of that in the past. It didn’t matter so much then but now I am in my seventieth year and only working part-time I respectfully declined the work. He insists though that he would like me to do all the other small jobs he had showed me downstairs in the weeks to come. That work is mostly replacing old for new switches, power outlets and light fittings and something I will gladly do for him. I think sometimes that people try to take liberties when they ask me to do work for them, I go to do some small job and they begin to add ‘extras’ and in this guy’s case and knowing my age and the fact that I only do small jobs on a part-time basis, he then asks me to rewire the top half of his house! Behave yourself!

Shirley Anne

Light duties

English: A selection of commercially available...
English: A selection of commercially available LED lamps (“light bulbs”) with Edison (screw-type) base/ Photo by Geoffrey A. Landis (Photo credit: Wikipedia)

E and I live in a rather large detached house that was built in 1877. When people ask about our house I tell them that it isn’t that large but we’ve already lost three butlers and four maids who seemingly have gotten lost in the place. Joking apart though it is large for just two people but once, a few years ago there were seven living here. It is classed as a seven bedroom house, four bedrooms on the third level and three on the level above. There are three main lounges, a family room which serves as a dining room and a small kitchen. Other rooms include an en-suite bathroom, a family bathroom and a wet room. there are four main rooms in the cellar together with three small rooms/stores and a hallway. Three more hallways/landings are on the three other floors. Attached to either side of the house are two garages. Quite a lot of space to hide away in and quite a lot of space to fill too! On Friday E and I went out shopping for some LED light bulbs (or lamps). Both the newly built wet room and the main/family bathroom (undergoing refurbishment at the moment) have between them 16 LED down-lights (recessed into the ceiling) and we want as many of the other light fittings in the house to have LED lamps in them. Some of the rooms are fitted with fluorescent fittings as the main source of lighting, some in the cellar, some at the top of the house and of course the garages. Some rooms have large chandeliers which have six to 10 lamps in them others have less. Some of the rooms have wall lights too, each with two lamps in them. We purchased enough lamps for three chandeliers and six wall lights which amounted to 27 lamps of three different types and all of them LED’s. They cost us a little over £170. Ouch! As an exercise and to determine just how many light fittings there are in and about the house I counted them all both inside and out and discovered that there are 124 lamps of different types and sizes. Some are large fluorescent tubes, some are LED floodlights, some are chandeliers with many lamps in them and the total number of actual light fittings amounted to 84! Phew! We reckon we will need to spend quite a few hundred pounds more yet to replace all those that can be replaced with LED lamps. Even the fluorescent tubes can have LED tubes fitted. That is a lot of money to spend out in order to cut down on running costs and the payback period will be measured in years however, the LED lamps are supposed to have a 30,000 to 50,000 hour lifespan under normal usage which works out to be quite a few years too. There will be a saving on power usage of course which means less to fork out for electricity and less demand on the electricity supply system.

Shirley Anne

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The wind blows

When the Wind Blows (1930 film)
When the Wind Blows (1930 film) (Photo credit: Wikipedia)

The wind blew cool as the day grew old
The sun was shining, so I’m told
But outside I was not to stray
For inside I was meant to stay
And the old wind still blows come what may.

 

Saturday was spent totally indoors as E and I did more work on the wet room. E managed to escape for a while as she had to visit the main Post Office in town but she soon returned. While she was out I lifted a floorboard on the landing above the wet room and installed another cable alongside the cable I’d installed for the shower in the family bathroom if and when we start its refurbishment. The final pieces of plasterboard went up on the ceiling then we measured the position of the six lights. With a hole saw in the drill I soon had the six holes cut and the wiring coming out of them. While I was doing that E unpacked the light units and partly dismantled them for me to fit into the ceiling. In less than an hour the lights were working. These lights are each 4 watt LED, a total of 24 watts but the actual light output is far in excess of the 60 watt tungsten light that was originally fitted. The actual amount of light from a tungsten lamp represents only about 7% of the 60 watts of power consumed, the remaining 93% is heat! The LED output is about the reverse, 93% light and 7% heat! Similarly, fluorescent lamps give out far more light than heat and that is why ‘economy’ lamps can be lower in power to give out the same light as the tungsten equivalent though they are not as efficient as LEDs. The downside is their cost but the upside is their lifespan. Anyway, that’s why we chose the LED fittings. Now the walls in this room have seen many changes in the lifetime of the house and the patchwork plaster is proof of that. I had added to it. Most of the plaster that needed patching up was where we had removed the wooden skirting boards so I used mortar instead of plaster and similarly I used mortar for filling holes in the brickwork that had been exposed. As the walls will be tiled top to bottom it doesn’t matter that mortar was used instead of plaster. One of the things we needed to buy was a vanity unit for the hand basin to sit upon and E had found a supplier of bathroom furniture who were far less expensive with their prices. When we priced the unit at Homebase it would cost a minimum of £104 without a top, doors or legs and with them supplied it would cost more like £340. This supplier had a similar unit for less than £80! We bought on online and went to collect it on Sunday morning. The store was in another town but it was worth the journey to go there. I also got to leave the house!

Shirley Anne