Basic Electrics

A good thing about this forum is it doesn't fuss about how and where questions are asked. But I see why Len and others might feel electrical questions posted under 'Electronics in the Workshop' might be a fa*ting in church, even though it isn't. In comparison a Basic Electrics topic is welcoming. Phil Whitley and Len get my vote; as a topic Basic Electrics is more likely to be used than Northumbrian, or Southern Q1!

Basic electrics aren't vintage or out-of-date either, it's all valid stuff.

Dave

There is a big difference between "Electricity at Work" and "Electricity at Home" - not the electricity it's self, obviously it is the same, although at work or in the larger homes there may well be 3 phase, which immediately increases the risk and danger to the untrained. But . . .the way in which electricity is operated and used is very different, for example, in the work place any 'work' on or near electrical apparatus MUST be covered by a 'safe system of work' requiring an 'isolation and locking off' procedure, and issue of a safety document to record the actions taken to prevent inadvertent electrocution to the person sticking their fingers on the conductors !

How many of us would do something like this at home, when you're next balanced on a pair of steps wiring in another 6ft tube in your workshop, ask yourself could your shmbo wander in and turn on the light and 'zap' you because you have only switched it off at the light switch rather than isolating it correctly ?

I would think that prospect wouldn't even cross our minds, or what about the four different things plugged into one 13A socket (I've seen the pictures on here of folks workshop set-ups)

How many Lathes and Milling machines are plugged in with a 3 pin 13A plug ? when it would be much better if they were connected to a 'dedicated fused spur' protected by a MCB of the correct rating ?

There are, I'm sure many of us who undertake 'home electrical work' and I suspect that a lot is not even close to meeting the requirements of the Institute of Electrical Engineers 17th edition Regulations.

If there are folk on here who can offer qualified and SAFE advice, then in my mind that has to be a good thing, and if the advice offered is dubious, then knowing how forums work, it will be corrected PDQ by someone who knows better !

Steve

Please explain why a small machine say 1HP or less shouldn’t use a plug .

What is wrong with 4 low power items plugged in 4 way socket ?

I have 9 pieces of machinery in my workshop and they are all fitted with good quality 13A 3 pin plugs, I cannot see anything wrong with that method as each plug can be fitted with a fuse to suit the load of the particular machine. I do concede though wiring fitted into a DP switched fused spur may provide a better connection in some instances where poor quality plugs and sockets are used.
Pulling the plug out of the socket ensures the power is isolated if changing belts, blades or other work is needed.
I also use a 4 way 13A extension lead with a computer and 2 VDU's plus a compressor when required.

In industry above 0.5HP motors require more attention and are likely to have a NVR starter and means of locking off the isolator supplying power to the starter.

Emgee

this is for a home workshop......

I have several machine at 3HP and 1x 5hHP, all 3 phase and they all have a plug........

correct for 3phase and size of power used..........

3 reasons,

1, it's a pain when I need to move machines in the workshop when tied to the wall.....

2, have an inate fear of the power being switched on by mistake when moving or working within/around the machines.....

3, In France the fixed to the wall type isolater was almost €125 each x the number of machines....expensive....

so the plug n play method saved me 2/3rds of the cost........

Also in France LeGrand is the only supplier of H/D electrical gear....and they have u by the short and curley's.....

so in my opinion there's nothing wrong with plugs n sockets provided they are QUALITY components....and within the amperage usage......

BUT

if running near max power for long periods then a dedicated supply must be used.....say a large comp, arc welder etc....

whilst on the subject of elec........

with exceptions I prefered the old fashioned wired fuse board......esp around the arc welder etc.....

where I used to live we got a lot of electrical storms, many a times I've had to replace an RCD or what ever they are called due to a close lightning strikes......once the house took a direct hit and it welded the 3 phase RCD main isolater together......that was €240 to replace, about 1/2 that in the UK.......

it seems to me most elec problems in the home workshop is nobody wants to spend the money to get a DEDICATED supply instaled.....a 2.5mm extension lead just cant hack it......

keep the electrical questions comming.........

I remember using a Desoutter ? drill many moons ago where I worked. It was silver and green, Ali, I suppose, and very powerful. Never saw them on sale anywhere, but years later I came across a drill stand to suit one of them and bought it for £7, then altered it to suit my Makita 1/2" drill and used it for years until I got rich and bought a floor standing 16 speed machine.. Still have the stand, now changed to suit another make. That stand was built like a battleship, no tinny bits there, cast iron base like a mill table, 1 1/2" upright.

Had a small Millers Falls 1/4" too, never see those around either

In those days drills had nothing fancy about them A drill was a drill was a drill full stop !

I can only conclude that for he purists it then does not need PAT testing.

regards Martin (Electrical and Electronics Engineer)

Hi Maurice.

The description of your profession makes my point exactly. There is a word of difference 'Electrical' and 'Electronics'.

Stepper motors, VFD's, digital tachometers, DRO's, Arduino micro-controls etc are a world away from repairing a 40 year old Siemens control board.

There is nothing wrong with running things on plugs or 4 way sockets. It's just a case of matching the supply capability to the current draw of the maximum load and sizing the plugs/wires/fuses correctly.

Easy to do for resistive equipment. A bit harder with motors. They have a momentary start current much higher than the running current. I'm sure you know this.

Or even the 18th editon of BS7671(the curent one)

Also BS7671 does not cover the wiring of equipment, just the fixed installation.
Most questions would be about equipment.
Nothing wrong with putting a small machine tool on a 13A plug. It has the advantage of easy nd 100% isolation for starters.

Robert G8RPI.

On the subject of extension leads..

Possible trip hazard as well !

(Brugge market 2005)

Hi, I doubt many people would get concerned about using their electric kettle being used frequently with a 13A plug, or if you prefer a BS1363/ BS1363/A plug. Most kettles will draw 2000w plus and I don't think many people would hesitate to re-boil a kettle a second time almost immediately after it's emptied. As far as I'm aware, a 13A plug can carry 13amps continuously, certainly for rewireable ones, however, non rewireable types are only rated by the manufacturer and the fuse must not exceed that stated on the plug and the fuse is only rated to protect the flex between the plug and the appliance it is connected too, whether it is a rewireable type or not, therefore if you have a flex rated at 3 amps with a 13A plug, it should have no more than a 3 amp fuse fitted. The fuse is not considered to protect the appliance or to prevent an overload.

Regards Nick.

Edited By Nicholas Farr on 14/07/2020 15:52:00

1HP (or less is fine) on a 13A plug, but the starting current (typically 4x running current) will be getting near to the plug rating, albeit for a short time, so plugged into a socket with nothing else will be fine, but it is often shared with other appliances and equipment and this is not so good.

Depends what you mean by 'low power' . . .the issue is that it is far too easy to overload the adapter and socket, plug using too many items at the same time, maybe not so much in a work shop enviroment, but we have all seen a TV, Video recorder, Lamp, and even a electric heater all plugged into one 13A socket - its a recipe for disaster !

Possible ?? I'd say a definite trip hazard !!

Looking at the plugs which are Blue, would suggest this is all running at 220/230 volts, and the trailing cables have no cover protection - a disaster waiting to happen

In the UK, electricity still claims on average 25-30 lives every year, the most common 'accident' is electrocution from Electric Lawn mowers and Hedge Trimmers (being used without a RCD protective device) and the user inadvertantly cuts the cable, and then 'fiddles' with the damaged part of the cable without isolating from the supply

These fatalities are so so easily avoided !!!

Evolution at work....

Thanks for replying to my post.

Hi, this is one reason people should know some basic electrics, as some adapters may contain a 13 amp fuse and the fuse does not just blow the moment more than 13 amps is drawn and of course those adapters without a fuse will deliver as much current that circuit will allow, i.e. a ring main with a 32 amp MCB and therefore you could get 32 amps plus flowing through your adapter rated only for a maximum current of 13 amps, that's just about two and a half times it's rated value and would more than likely to get extremely hot and even burn. Of course the same thing about overloading will apply to multi gang extension leads.

Regards Nick.

There's a Nikola Tesla in waiting in all of us , HSE would have done for him, imagine no ac.

I remember when it was common to plug electric irons into lighting circuits via adapters. Don't remember there ever being an issue with this. Is perhaps the fear of things going wrong greater than the reality. have had to rectify some very dubious wiring in some of the houses we have bought, e.g. lighting cable with legnths with no insulation, a 13 amp socket wired with 2 core orange cable. Clearly the previous occupants had lived with this with no consequences.

For basic electricity, best remember never to do any DiY whilst in the bath , after that, never forget to light the gas if you turn it on. No-one ever seems to worry about gas anymore despite some pretty impressive gaps in houses when mistakes occur.

It's said that Edison promoted his electric chair partly to discredit Tesla's AC.

Neil