How to read electrical drawings (i can't)

[Shaun12]

For the past few years i've been working as an installation electrician. Mostly working on industrial sites and projects. We will install wiring, containment, panels and motors. I would say i'm pretty confident with any of that. I passed all of my exams throughout my apprenticeship without an issue and found the AM2 relatively easy.

However, recently whilst on a job we were asked to fault find in a panel that had had a fault on the security circuit for a piece of automated machinery. I was handed a set of drawings and being completely honest i didn't have a clue where to start. I have somehow managed to go through an entire apprenticeship without having to read a drawing to fault find. Luckily for me in this situation, the guy i was working with knew what he was doing so he lead the fault finding.

I guess i have just never faced the situation on site until now. At the moment these drawings might as well be in Japanese. How can i learn in my own time how to read them and be able to fault find using them? Does anyone have any tips or any suggestions on reading material or videos...

I feel pretty embarrassed about this....

 

[Darkwood]

Hi- welcome to the forum.

Standard Electrical courses have never touched on panel control board schematics so I wouldn't be embarrased, been asked to fault find on a safety critical control system without knowledge is altogether a different issue, I would remind them you are trained as an Electrician and not an Electrical Engineer and if they want to 'as a company' get involved with the panel control systems then fine as long as your mentors have the qualifications, competence and Insurance to do so. I find a lot of bog standard Electrical companies dipping their fingers into machinery control panels and basically making a right bodgit, sometimes dangerous repairs, additions etc.

If your company has declared this kind of work to their insurance and you have a competent, trained Electrical Engineer to guide you then you are in a unique position to learn a side of the trade that has a massive shortage of skilled persons and it will almost guarantee your future so I would in your shoes - embrace this opportunity and enroll in further education to get you up to speed with machinery control systems.

 

[Shaun12]

Hi Darkwood, thank you for the reassurance. The company i work for do build, install and commission panels and the site we were working on has numerous panels built by the guys in the workshop. This is something i'm interested in, i feel it is a skill i need to have now. Can you recommend a way i can teach myself or are there any online courses or tutorials you could point me in the direction of?

 

[telectrix]

Hi- welcome to the forum.

Standard Electrical courses have never touched on panel control board schematics so I wouldn't be embarrased, been asked to fault find on a safety critical control system without knowledge is altogether a different issue, I would remind them you are trained as an Electrician and not an Electrical Engineer and if they want to 'as a company' get involved with the panel control systems then fine as long as your mentors have the qualifications, competence and Insurance to do so. I find a lot of bog standard Electrical companies dipping their fingers into machinery control panels and basically making a right bodgit, sometimes dangerous repairs, additions etc.

If your company has declared this kind of work to their insurance and you have a competent, trained Electrical Engineer to guide you then you are in a unique position to learn a side of the trade that has a massive shortage of skilled persons and it will almost guarantee your future so I would in your shoes - embrace this opportunity and enroll in further education to get you up to speed with machinery control systems.

and get the company to pay for it.

 

[Darkwood]

Hi Darkwood, thank you for the reassurance. The company i work for do build, install and commission panels and the site we were working on has numerous panels built by the guys in the workshop. This is something i'm interested in, i feel it is a skill i need to have now. Can you recommend a way i can teach myself or are there any online courses or tutorials you could point me in the direction of?

I would show your enthusiasm with your work management and ask them where you can further your education, maybe an Engineering course is where to be looking -TBH getting through to be an Electrician nowadays is a walk in the park and requires little skill-set and education like it used to but to learn this side of the business is not by any means a walk and will be a big uphill climb as their are several sets of regulations to cover as well as several areas you could move into like PLC design and programming, motor control etc etc and it may be a decade before your in a comfortable area where you can look and say 'I'm know my job, and I'm up with the regulations enough to carry myself'.. .. I been doing it 25yrs and on a weekly basis I have to research stuff to resolve issues on old equipment and how to achieve the same with modern tech'.

 

[tazz]

With any schematic drawing there should be a symbol key, showing each item, if not request one

 

[Darkwood]

With any schematic drawing there should be a symbol key, showing each item, if not request one

Sounds like his company make these panels Tazz and I assume they do have schematics with keys but the complexity of control panel schematics do take a learning curve to simply read them even when all the info is provided... it took me a while to get the lay of them if I recall but it don't help when the Key is missing its non'standard format and in the wrong language, if your lucky to be blessed with any plans at all

 

[Shaun12]

Thanks for the response guys. However, there is pretty much zero chance of work putting me through a course. There were 2 people made redundant last week and i'm probably one of the next inline as most of the others have 10 yrs plus service. Surely theres something out there i can do in my own time?

 

[Darkwood]

Well its just start with the basics and learn that way.

It took 10seconds to find this PDF so have a search yourself - some areas might be obvious but it will give some direction your after...http://www.modon.gov.sa/en/mediacenter/InformationCenter/Books/Industrial Control Wiring Guide.pdf

Also look at borrowing a copy of the BS60204-1 from work and learning the regulations that guide general machine wiring practices this will help a lot to understand how things like the colour of control cables denotes the job and voltage range they are used for which has little connection to the wiring colour codes you learned about.

 

[Shaun12]

Thanks, I'd say most of the info in that pdf i'm fairly comfortable with such as how to run cable, loom and terminate etc. What i don't have any clue on is things like how to navigate a drawing spread over multiple sheets of a4. For example all of the reference numbers, page no's etc.. I'm fairly confident it's pretty simple once you have been shown. I search all sorts of things like "how to read panel drawings" "how to read electrical drawings" etc on google/youtube but it never really throws up anything it seems to be mostly drawings relevant to electronics.

 

[Darkwood]

You clearly work for a company who design and provide their own schematics, I would try get a 20min chat with one of the designers and he should be able to point you in the right direction as to page numbering sets and codes... usually the schematics are layed on a grid format (grid may be shown or not but the edge references will be)and when a wire exits a page it will have a page reference and grid/column number so you can jump straight to the line you are following.

 

[Shaun12]

yeah you're correct. Although i'm out on site al day so driving to the office to speak to someone in design isn't really a possibility.

This thread is exactly what i'm talking about

http://www.electriciansforums.co.uk/commercial-industrial-electrical/53115-electrical-diagrams.html

So in that drawing the contactor in question is 20Q1? The terminals are the numbers 1-3-5 (top) and 2-4-6 (on the bottom) will these numbers be on the actual contactor or is it just a reference for something on the drawing? 22/33 would be aux contacts?

I find this stuff so much more interesting than bending conduit and fixing panels to the wall. i'm really keen to learn this

 

[Darkwood]

yeah you're correct. Although i'm out on site al day so driving to the office to speak to someone in design isn't really a possibility.

This thread is exactly what i'm talking about

http://www.electriciansforums.co.uk/commercial-industrial-electrical/53115-electrical-diagrams.html

So in that drawing the contactor in question is 20Q1? The terminals are the numbers 1-3-5 (top) and 2-4-6 (on the bottom) will these numbers be on the actual contactor or is it just a reference for something on the drawing? 22/33 would be aux contacts?

I find this stuff so much more interesting than bending conduit and fixing panels to the wall. i'm really keen to learn this

They are one variant you may find on the contactors likewise it may say L1 L2 L3 etc just look up contactor pics and see the different ways manufcturers label the terminals but 1-3-5, 2-4-6 is a recognised format... although this is ident of device only, the cables will have most likely other numbering systems that connect to them so its recognising what is what really.


20Q1 looks like a overload trip device for a motor
the K1 and K2 devices are contactors possibly forward and reverse options

 

[edexlab]

This is an American article so some symbols do differ slightly but I found it useful to start reading ladder diagrams


https://www.google.de/url?sa=t&sour...TOWAeQ&usg=AFQjCNHbvyerMSdyEaWPR5AwO8ZGNOFYUw

 

[Shaun12]

Hi thanks for the link, it doesn't seem to work for me, could you possibly try again so i can have a look? I'm actually quite handy with ladder logic/ PLC's and programming..

 

[edexlab]

I've just tried it and your right it's not working , I just typed in
"reading electrical ladder drawings " to Google and this was an article for

"m ecmweb.com>Basics "

It just shows/explains the format or layout of a ladder diagram ie input/ output devices positions rungs and numbering ,Nc/No contacts might be too basic for you perhaps

 

[Shaun12]

oh ok. What I'm going to do is get some drawings from work and anything i'm not sure of ask here. I'm sure it will help others as well

 

[Spoon]

oh ok. What I'm going to do is get some drawings from work and anything i'm not sure of ask here. I'm sure it will help others as well

Good idea.

 

[edexlab]

I'm in the same sort of situation , although I do work in the factory as well as on site, the company here likes you to learn off your own back so I started looking at the drawings doing some research online and trying to figure out what's what,
their drawings are a bit different from conventional drawings and people here are not always forthcoming with information, some are good, but I don’t see them much
but the overall culture is to find out yourself !

The best thing I've done to improve my understanding was to take the drg and trace it through panels referencing the control drgs ( during my lunch ) starting from the incoming isolator all the way through

This made it all make much more sense!

Then I got lucky and got the chance to work on a machine with an engineer

I had to trace through all the circuits and check them against the drawing removing any unecessary modifications (machine was an experimental ) and then redoing it to his design.... this was a really good experience tbh and I feel I'm getting somewhere now