# Forum More Stuff Debate & Technical Discussion  Isolation procedure - for discussion only.

## elkangorito

As the title suggests, I have put together an isolation procedure *for discussion only!!* I do not want anybody to use this procedure until it has been thoroughly discussed. 
It may seem a little "over the top" for some but I've tried to be as safe as possible. Please feel free to comment.  _There is a picture attached, which can only be viewed if you "sign in"._    *Isolation & "proof" of isolation procedure.*  
Firstly, some assumptions must be made. They are; 
1] You know the location of the Main Distribution Board (Meter Box). 
2] All equipment within the meter box is clearly labelled or easily identifiable. 
3] The installation (the house) is properly earthed via an earth stake. 
4] You possess and know how to use a multimeter (preferably "digital"), which is to be in good working condition (no loose, frayed or damaged test leads. The entire insulation is to be intact). 
5] You are able to identify a circuit breaker, an RCD, an HRC fuse (Service Fuse), a rewirable fuse, a Main Switch. 
6] You WILL NOT carry out this procedure alone. Somebody must be with you at all times. 
7] Your hands will be clean and dry. 
8] You WILL NOT carry out this procedure in bare feet. Safety shoes/boots with socks are prefered. 
9] Watches, rings and any metallic jewellry are to be removed prior to commencement of work. 
If you (or the installion) can't/doesn't comply with any of the above, DO NOT PROCEED!!    *Procedure No 1. (quite safe).*  *1]* Verify that the multimeter is functioning correctly for voltage measurement.  *a.* Find a couple of GPO's (power outlets) that you know are working. Ensure that they are switched off before going to step "b". *b.* Switch on the multimeter and ensure it is set to measure AC voltage (~). If it is not autoranging, set the range to 500v. *c.* Standing in front of the GPO and ensuring that it is NOT switched on, insert the black lead into the verticle slot, which is beneath the other 2 slots. This is the "earth" slot. It is important that you place a lead into this slot first and not into one of the other slots. *d.* Place the remaining lead into the top left slot, which is the active slot. *e.* When both leads are securely in their slots and with one hand holding onto both leads to ensure that they can't come out of their slots, switch on the GPO. *f.* You should read a voltage of between 230 and 260 volts. This will prove that the multimeter is working correctly, you have an earth as a voltage reference and that the GPO is wired correctly (Active is the top left slot). If you read zero volts, the GPO may be wired incorrectly. If you read any other voltage, there could be a problem somewhere. *g.* Switch off the GPO and remove the "active" slot lead and insert it into the neutral slot (top right). *h.* You should read zero volts. *i.* Switch off the GPO and remove the "neutral" slot lead first, then remove the "earth" slot lead. *j.* Insert both of the multimeter leads into the active and neutral slots. *k.* Ensuring that one hand is holding both leads firmly in place, switch on the GPO. You should read a voltage of between 230 and 260 volts. *l.* Switch off the GPO and remove both leads simultaneously. *m.* Go to the other functioning GPO and repeat steps a to l.   *2]* Now that you have verified that your multimeter is working correctly, it's time to "isolate".  *a.* Locate the Main Distribution Board (meter box). *b.* Locate the Main Switch (there should only be one Main Switch) within the meter box and switch it off. If there is more than one switch labelled as "Main Switch", switch them all off. *c.* Switch off all other circuit breakers, RCD/CB's etc and/or remove all fuses. DO NOT remove the Service Fuse, which is usually "sealed". It costs money to replace "seals". *d.* If the meter box is lockable, lock it (temporarily and with your own lock) so that nobody else can gain unauthorised access. Put the key to the lock in your pocket. *e.* Go back to the two GPO's that you used to verify that your multimeter is working correctly and check both GPO's again, using steps a to l in 1]. You should read zero volts for all checks of both GPO's. If you DO NOT read zero volts, you MAY NOT proceed with any further works. It's time to call an electrician. *f.* If you are sure that there is zero volts, prepare to commence work.    *3]* Checks prior to commencing work.  *a.* Ensure that you test for voltage using an earth reference before you commence work on any equipment. For example, you wish to change a light switch. If the light switch DOES NOT have an available earth wire (it usually won't), you will not be able to determine whether it is safe to work on or not. In this case, I would suggest that you DO NOT proceed with the work. *b.* If there is an available earth wire, set up the multimeter as before (500 volts AC). Ask your friend to hold the multimeter for you and then place one lead on the earth conductor FIRST! Place the other lead on any and all other conductors. You MUST read zero volts on all conductors before you can safely carry out any work. If you detect any voltage, do not proceed!!

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## Master Splinter

I use one of the no-contact 'live wire detectors' - chirps when you turn it on (to let you know that it is working) and makes a noise like a demented cricket when you put it near a live wire. 
I don't have all that much trust in the bottom end $20 multimeters when it comes to mains voltage.  Too 'made to a price' for my liking.

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## elkangorito

Hi Splinter.
I don't trust anything that's "cheap". Mind you, the following thing is cheap & very effective. 
As part of my apprenticeship (1st year), I had to make a set of "test lamps". The set comprised of two 240 volt, 15 watt incandescent globes connected in series, which were totally encapsulated on grey PVC conduit. The leads were purchased from Dick Smith or were made. The "home made" leads were the best.
When connected across a 240 volt source, they would dimly glow. When connected across 415 volts, they would shine brightly. 
Of course, if the globes didn't light up at all, it meant either no voltage or a blown globe. For these reasons, one always had to test their "test lights" with a known "active" source to ensure that the globes were functioning.

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## chrisp

A couple of observations:  I heard you can fail isolation exams if you, like I do, switch your multimeter off between the live test and the dead test.  I've heard that you should leave your meter on, and in the same setting, between the live and dead test.From personal experience, I've noticed that a very well know brand of multimeter reads wrong when the (flat) "battery" symbol is displayed.  The meter appears to work alright, and often gives close to right readings, but I wouldn't like to trust my life to it.
Any thoughts on the idea of deliberately shorting wires out to make sure they are dead?  I'm a bit of a chicken and don't like bangs or sparks myself.  :Redface:

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## Gooner

> shorting wires out to make sure they are dead? I'm a bit of a chicken and don't like bangs or sparks myself.

  I ask my wife to hold the exposed wires. If she starts shaking, I know they are live. This is why it is good to do these types of jobs with two people.

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## watson

Gooner, Gooner, Gooner.
Bet you can't get her to help more than twice though!

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## Spider Webb

My 2c for added "over the topness"  
0.7 Have an offsider who is trained in CPR/Live Low Voltage Rescue Procedure with a Low Voltage Rescue kit laid out ready for use with all items of kit checked for use.Effective proven communication for use in emergency.  
0.8 Hold a pre work brief with said offsider discussing the work to take place and any hazards that may be encountered with controls put in place to reduce the risk. (Throw in a Safe Work Method Statement here also)  
0.9 Wear appropriate PPE in case of flashover/touch potential/wrong category meter used when testing (Face shield, Insulated gloves, buttoned up neck to toe 185gsm clothing, rubber soled safety boots, rubber mat.......) 
2 d.1 Attach Danger Tag to locking device, indicating who placed it, reason for isolation, estimated time of restoration with phone number. 
2 e.1 Check meter on a known live source again to check it didn't fail after initial live test. Chrisp's point 1 obsevation comes into play here. 
Stewart

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## Bros

When I first started switching HV 300kv all we had for PPE were longsleeve shirt and insulated gloves. It hasn't changed to much since as it is not possible to use flash coats in an outdoor switchyard however flash coats were used on 6.6 kv metal clad isolation and high fault current 415v switching.
You had to have a competent person with you capable of giving resus but we didn't think that would have been of much value as the flash burns would have been the main problem. 
It was alway interesting to say the least when closing an isolator while standing near a 5m tall CT.

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## elkangorito

> A couple of observations:  I heard you can fail isolation exams if you, like I do, switch your multimeter off between the live test and the dead test.  I've heard that you should leave your meter on, and in the same setting, between the live and dead test.From personal experience, I've noticed that a very well know brand of multimeter reads wrong when the (flat) "battery" symbol is displayed.  The meter appears to work alright, and often gives close to right readings, but I wouldn't like to trust my life to it.
> Any thoughts on the idea of deliberately shorting wires out to make sure they are dead?  I'm a bit of a chicken and don't like bangs or sparks myself.

  *For some strange reason, I can't reply to your post if I "multi quote" it.* 
Anyway, with regards to 1., yes, I would certainly advise leaving the meter on.
With regards to 2., I would assume that a preliminary test would solve this problem, although it is a good idea to make sure that "good" batteries are being used. My simple rule is that if the batteries are about one year old or older, I replace them regardless of their condition.

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## elkangorito

> I ask my wife to hold the exposed wires. If she starts shaking, I know they are live. This is why it is good to do these types of jobs with two people.

  There's no doubt about you Gooner...you're a funny bugger. A word of warning though...if your missus should suddenly buy a new knife sharpening device as well as a meat cleaver, you may like to wear a steel neck brace.  :Biggrin:    

> My 2c for added "over the topness"  
> 0.7 Have an offsider who is trained in CPR/Live Low Voltage Rescue Procedure with a Low Voltage Rescue kit laid out ready for use with all items of kit checked for use.Effective proven communication for use in emergency.  
> 0.8 Hold a pre work brief with said offsider discussing the work to take place and any hazards that may be encountered with controls put in place to reduce the risk. (Throw in a Safe Work Method Statement here also)  
> 0.9 Wear appropriate PPE in case of flashover/touch potential/wrong category meter used when testing (Face shield, Insulated gloves, buttoned up neck to toe 185gsm clothing, rubber soled safety boots, rubber mat.......) 
> 2 d.1 Attach Danger Tag to locking device, indicating who placed it, reason for isolation, estimated time of restoration with phone number. 
> 2 e.1 Check meter on a known live source again to check it didn't fail after initial live test. Chrisp's point 1 obsevation comes into play here. 
> Stewart

  Some great thoughts Stewart but some are a bit "over the top" for domestic work (in my opinion).
PPE gear is really only for situations where a high level of fault current is likely and/or high voltage is apparent. Neither of these conditions occur with domestic installations. 
Danger Tags are always a good idea, even in a domestic situation if you want to be triple sure. Personally, I find a lock & a key (key in my pocket) is more than enough safety for domestic work. Of course, if things aren't lockable, danger tags are not a bad idea.   

> When I first started switching HV 300kv all we had for PPE were longsleeve shirt and insulated gloves. It hasn't changed to much since as it is not possible to use flash coats in an outdoor switchyard however flash coats were used on 6.6 kv metal clad isolation and high fault current 415v switching.
> You had to have a competent person with you capable of giving resus but we didn't think that would have been of much value as the flash burns would have been the main problem. 
> It was alway interesting to say the least when closing an isolator while standing near a 5m tall CT.

  I think this highlights the power of electricity. Although I've never had the pleasure of being employed as a HV switchyard technician, I've been exposed to such scenarios. During my apprenticeship, we built "skid mounted" 11kV/66kV substations for open cut and underground coal mines, which were also tested by us. The 11kV was for underground. The safety precautions back then (1980's) were mind boggling. 
Thank god the domestic DIYer does not have to deal with this stuff.  
Does anybody have any ideas about deletions/additions or any other edits to the isolation procedure?

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## Bros

> Although I've never had the pleasure of being employed as a HV switchyard technician

  Consider yourself very lucky. The main requisites for a HV switching officer was 
1 Ability to read simple schematics
2 Ability to read switching sheets.
3 Strong back to lift PED's on the end of a 6m fibreglass pole to clamp on to the conductors.
Being an electricain was not a prerequisite as we had mechanical fitters even a baker was trained as switching officers in the switchyard where I worked which was one of the largest in Queensland

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## rrobor

Meter thingy is wrong, buy a quality Fluke meter today and its auto shut off after a few minutes of non use. Bad job if you fail your exam cos your $700 meter shut off. Also many men would refuse to remove a wedding ring. Oh and how do you rate the bling kids stick through themselves, Bad job if they have to strip to remove nipple rings and the like.

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## Master Splinter

[quote=rrobor;766249 Bad job if they have to strip to remove nipple rings and the like.[/quote] 
Or - fault current to earth through a Prince Albert piercing...that would really be 'stupidity is its own reward'!

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## elkangorito

> Also many men would refuse to remove a wedding ring. Oh and how do you rate the bling kids stick through themselves, Bad job if they have to strip to remove nipple rings and the like.

  ...and many men have been injured or killed as a result of not removing rings etc. 
Can you please translate this into English;  

> Oh and how do you rate the bling kids stick through themselves

  I do recall a conversation once. It was about hair & atom splitting. 
Have a totally lovely day. :Roll Eyes (Sarcastic):

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## rrobor

Tist tist you are not a bling wearer are you. Bling is the bangles and baubles the in crowd wear. Think it started with gay men now its just the slightly over the top stuff that brighten up the nondescript. Try a bit and let your little light shine. Oh the hair and atom thing, you probably mean  string theory and atom splitting. Cripes if you start on that I'll have to pull out my Stephen Hawking collection.

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## elkangorito

Are there any further "sensible" comments regarding this thread?

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## Bros

And I thought it was a new thread but it is an old one that has run out of steam. 
Turn the lights out and move on.

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## watson

Click

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