3 phase motor rotation direction

Hi Kinlet Hall 4936, I don't have any certificates for electrical work myself, but I did used to work along side of many electricians in a previous employment in a maintenance department and understanding basic electrics was beneficial to the job. I have done electrical wiring in houses that I've lived in including rewiring my brothers house some 40 years ago which are all still standing. The last dwelling that I lived in I done some modifications on before the current legal restrictions came into force, and around two years ago it was fully tested by a competent registered electrical engineer for fire risk assessment reasons, and the only faults (which were minor, and were not regarded in need of any attention) were those that were put in place by the so called qualified electricians before I ever lived there. Yes I've seen some pretty dodgy wiring by so called qualified electricians in my time and even in the not so distant past.

I have qualifications in welding to technician level, now I could say that all the DIY welders out their are risking burning down their sheds and garages or even giving themselves very serious burns and injury to their person, or others, or even having something seriously fail and kill someone, because they have not welded it correctly, because they are not so called qualified welders, but I trust the majority of people will take utmost care in what they are doing and not go beyond their limits.

While I believe I am capable to do basic electrical work, and I did build all my own Disco equipment right down to component level many years ago, which never failed or caused any problems in all the venues that I worked in, I would not consider myself capable of going into a factory and modifying an electrical control panel. I do believe I know what I should not attempt in this area. Just because one has not got the so called qualifications doesn't make one ignorant to the tasks that one is embarking on.

Rgards Nick.

As a guess, I'd say ChrisH's lights had been wired in series?

By the end of this century any survivors will only be allowed 12v DC and need a certificate to make water luke warm, boiling not allowed since 2050, while crawling around on all fours lest they trip on an uneven floorboard.

Oh my, did somebody voice a different point of view?

Two bulbs wired in series? Remove one and the other gets brighter? Now I just HAVE to see that

Illustrates my point exactly!

Hi Kinlet

We both know the risks and have had to pick up the pieces when deaths have followed the work of poor professionals and amatuers who have not got away with it that time.

I suspect that we both know why the electricity board did away with testing and connection of new work, cost.

The detractors on here will nver have to see what we have seen, but will not listen, as they always know best.

Ian

Hi Kinet,

Chris did say that there were two light fittings each with two bulbs in. So I think he is implying that the bulbs in each light fitting where correctly wired in parallel but the two fittings were wired in series. So if he removed one bulb in fitting A then the other bulb in fitting A would become brighter. It would have been clearer if he had added that the bulbs in fitting B became dimmer.

Les.

I was pulling your leg - you had no idea - yet the reason was so blooming obvious! The lights were wired in series. Made no mention of the lamps....not that I'm that bothered. Point is our resident expert didn't have a clue! Time to dust off your books lol.

Edited By MAC on 04/03/2012 10:29:07

Hey Guys, especially Kinlet Hall, cool it! This thread is getting far too heated and vitrolic. One of the points I was making was that you can have all the theorectical qualifications in the world, but if you don't have the practical skills to go with it then it counts for nothing - the guy with the engineering degree and thesis on boilers was an example.

This thread was started by someone wanting to know why a certain action had a certain effect, he didn't need to know why to do his job but he wanted to broaden his knowledge. Good on him. How many people out there drive cars without a clue of what goes on under the bonnet? The thing is, they don't need to know that just to drive a car, they just need to know certain actions have certain effects and if it the action doesn't have the effect it should it means something is not right. Knowing why is an extra bonus.

Yes I totally agree electricity is dangerous, as Kinlet says you can't hear, it see it, or smell it and if you feel it then usually it's bye-bye - which is why I never trust anything with wires coming out of it! But it wasn't so long ago that most electrical appliances sold in the UK came without a three pin plug. As for some reason sticking the bare ends of the wires into the socket held in by matches was frowned upon, you then annoyingly had to go out and buy a plug which usually came with the one fuse you didn't need, a 13amp instead of the 3 or 5 amp fuse you did need. So how many 3 pin plugs were fitted everyday by the unqualified and unregistered Joe Bloggs of this world, with the wrong fuse, but you never heard stories everyday of disasters arising out of this. In fact I've never heard a disaster story arising from that practice.

The other main point I was making was that those of us who indulge in model engineering use a variety of tools, like lathes, milling machines, drills, welders, grinders to name but a few, all of which can be dangerous if mistreated or mis-operated, and we make stuff out of stock material, assemble it and make it run whether be by air or steam or internal combustion or hand. This means we are careful, thinking and practical people who have a number of varied skills, estimating the material required, cutting out said material, marking out, machining fitting, etc., who are unlikely to do stupid things when doing simple electrical work, and with all due respect to all the good electricians out there, house wiring is pretty basic stuff compared to some other electrical installations.

So Kinlet, I am disappointed that with all your electrical qualifications and experience you couldn't work out what I was saying, perhaps you were looking too deeply, but you did add that you obviously know ABSOLUTELY NOTHING. So for your benefit and at your request, here are the details you are FASCINATED to know about to make things clearer for you. As MAC and Les had deduced, the light fittings were wired in series, the bulb holders within them in 2 bulb fittings are prewired in parallel. Usually. As for the ring mains, well, before the EU messed wiring colours up, twin and earth wiring came with sensible and obviously different colours with red as the live wire. In a ring main the red live wires at the two ends of a ring main circuit are connected together to the bottom of the fuse that serves that circuit in the distribution board. No MCB's in those days. So what had happened here was one red live end from ring main one had been fitted to fuse one, and the other red live end of ring main one to fuse two. Similarly, one red live end of ring main two had been fitted to fuse one and the other red live end of ring main two had been fitted to fuse two. Simples, even for a non-electrical engineer like me to see. Now that meant that the whole house had effectively one huge ring main, fed by 2 live feeds through two fuses. Which didn't seem to me to be quite right somehow, nor safe, but what do I know, I'm only a mechanical engineer! I do hope that explaination makes it all clear now for all. Phew. Time for another lie down in a darkened room!

Chris

PS Sorry this post had to be so long!

Edited By ChrisH on 04/03/2012 12:23:02

Edited By ChrisH on 04/03/2012 12:24:24

Edited By ChrisH on 04/03/2012 12:32:46

There seems to be an obsession with red cable on this thread. the most common form of colour blindness is an inability to recognise the difference between red and green. Blue can be recognised by all but those with total colour blindness. To complicate matters those with red blindness see red as black. Many with colour blindness do not realise unless they are tested.

Around 7 to 8% of men have colour blindness so a good proportion of electricians are liable to suffer from the condition. The blue brown yellow/green colour scheme was adopted for flexes in the early 1970s.

ChrisH,

If you edit a entry so many times, you can always "edit" the previous "Edited By" as well, does not look quite so bad.

No obsession with red - just trying to make the point as clear as I could for those who couldn't figure it out for themselves! If someone is that colour blind they cannot distinguish red from black then I suggest that they don't do electrical wiring.

In poor light the difference in modern colours are harder to determine than the old red/black I find, or I could just be getting old!

Thanks KWIL, never too old to learn about this new flangled stuff!

New regulations are certainly well intentioned. Who wouldn't want to see electrical installations being made safer?

I dislike that the implementation of Part-P is so dependant on paperwork and certificates, and whilst avenues for competent DIY work do legally exist, I have found that such avenues can be made tortuous by local authority building control policies.

The approach of simply refering all work to a qualified person seems somewhat blinkered to me. Efforts to restrict the availablity of materials to professionals is simply protectionism.

There will always be people who want to do their own work, either because they enjoy it, because it is more convenient for them, or because of financial pressures. Refering everyone to a professional is futile and will be ignored in many cases, I believe it is better that good quality, freely available information should exist about how to do a job safely.

I have a concern for future generations, who will grow up never having fitted a three pin plug; there probably won't be DIY books containing detailed explanations and pictures of correct domestic wiring for much longer - so how will future generations be able to instinctively spot something that needs attention? How can we expect our children to become interested enough to want to pursue a career in technology, if we don't let them get some hands-on basic practice?

Now that we have sunk to the level of 'ad hominem' attacks I feel that I am wasting my time here. As Ian Hewson has very sensibly said' you know best and will never listen'

Thank you so much for elucidating ChrisH - such a pity you weren't quite so erudite in the first place

As I have already said I feel that this has now become a total waste of my time and this will be my last post on this subject

In fact it will be my last post here on ANY subject as there seem to be so many 'armchair experts' who have an opinion (right.wrong or irrelevant) on just sbout EVERY subject raised here and appear to come here for no other reason than to see their (often totally irrelevant) views published. I feel being in the workshop will be far more rewarding

So carry on sharpening your slitting saws and electrocuting yourselves - Quite simply my dears - I don't give a damn

A few things to observe

1 OP stated they knew that swaping the phases changed drection but not WHY

there followed a good description /explaination...better than I could offer without , phasors ,vectors and lead /lag discuions

2 someone expessed their opion that in effect if you dont know what you are doing then leave it to a proffesional

there followed " I have seen xyz dodgy wiring from abc proffessional / diyer etc" and it all got abit tense

I too have seen shocking[ no pun intended] premise wiring.

Enough so that I don't even assume earth is earthy.

3 since this topic is way off topic.PAT [testing]

chinese IEC leads live and neutral swaped, earth WIRE missing

[part code for Euro three core] dummy green wire no copper

other leads..iron/steel substituted for copper core

fuses made to look right but in effect printed steel...the preverbel 6" nail

Lap top PC power supplies that make casing of laptop run at 300 to 400 V above earth

[these actualy meet spec...US market psu's]

Do I have apoint? Only one

Be careful..that brand new house could still be lethal as might the new 42" plasma.

peace

Everyone has to make their own judgements about what they are com[petent to do. Unfortunately my experience suggests that the more experienced you are the more you are aware of your shortcomings. I've been playing with wiggly amps since about 13, but my Dad ran his own business TV rentals and repairs, wiring houses etc. and taught me a lot. I don't trust any wire to be isolated and wire plugs so that the earth lead will pull out last.

I'm sure I could do work on gas, but I don't know enough and get someone it for anything more than changing a bayonet fit cooker.

The last electricity horror story I heard of was a phone charger - left on all weekend under a pile of paper - only dissipating a few watts, but well insulated...

Neil

I must admit to wiring my own workshops and any house wiring, only with the lowly help of a hnd level electrical engineering course. My father was a service engineer for years having worked for the docks in london, the royal mint and many firms that installed letter folding machines. I was bought up running 3ph, rewiring our own machines as running a small joinery firm we couldent afford to have a machine shut down for a day till joe bloggs sparks comes who wants to knock the job out in 15mins and bill you for 4hrs work. We repaired our own machines because we had service engineers out at £400 a day who left our machinery in a state that didnt work and was so far out of alignment it was beyond a joke.

Iv also worked on a building site where I cut through a live cable somebody had run through a doorframe attached to a newel post the door frame was actually nailed over the cable. Luckily nobody was injured but it beggars the point who put it there?

Lets be frank on points there will always be dodgy people and cautious people having a piece of paper just means you know the risks not that you care what they are or are going to make sure they are abated. Not offering those in need of advice the relavant information for there own safety and to allow them to understand there limits or the dangers of there actions is far worse then telling them the truth. Mr hall your experiences must have been life altering but getting a snotty and presumptive attitude will not stop those intent on doing there own works from doing so. You have only alienated them from your wealth of experience and advice which I believe is completely counter productive to your point.

The more you make out a subject is taboo and beyond the comprehesion of the layman the more you foster a false sense of understanding when said layman figures out how to wire a plug, then a motor or a machine. Then runs simple lighting and sockets ect. Its the same rediculos attitude the government took to drugs education in the 80's and look where that got us. People dont like there intelligence insulted wether it founded or not. And by doing so you will only alienate people not educate them.

This forum is by far the most intelligent and senseable Iv had the pleasure to come across its an oasis of sense in a world of stupidity. Model engineering by its nature is time consuming, pains taking and technical not areas appealing to those lacking in grey matter. A well placed piece of advice will save many more lives then jumping on the qualifications pedistal.

I would agree that many people could make a workmanlike job of a domestic electrical installation. The parts where people fall down is the design part of an installation where most will not have a clue where to begin and the testing of the completed installation where most people will not posess the test equipment or knowledge of how to use it. As usual the dangerous people are the ones who think they know what they are doing but don't know enough to realise that they don't know what they are doing.

Mike

Exactly Michael, as I was saying people think they know what there on about until they get shown what they dont.