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Posted By Topic: Electrically Unsafe Standard.....??? RCD Testing

Brian W
May 06 2013 21:29

A discussion at work this morning needs some clarification.

AS/NZS 3000:2007, 8.3.10.2 (Testing) states that an RCD can be tested by "operation of the integral test device" or "by use of test equipment" and note 1 states that (paraphrased) "if the RCD being tested is a type A, the resdiual pulsating direct current test may be omitted"

and ESR 24 (3),(4)and (5) states that an RCD is electrically unsafe if fails to "interrupt to current in all live conductors within" 30mA/300 milliseconds, 0.5/0.15 or 10mA/40mS (depending on clause)

and, fitting unsafe equipment is a Grade A offence...

Then surely clause 8.3.10.2(a)of 3000:2007 is an unsafe act, leaving us open to prosocution for a grade A offence, because by simply pushing the button we have no way of knowing the tripping times or current.
   

CraigG
May 06 2013 22:04

Another stupid clause.

What it means is that "Yes press the test button" , we accept that.

But please ensure it trips within these set times.........


That would be impossible to know if you dont use correct test gear.


They could have saved a shit load of ink and bullocks if they just simply stated the rcd must trip within these XXXXXXX times.

Why bother writing that other thing saying pressing the test button is acceptable when it is quite evadent that by doing that alone you cant possibly ensure complete compliance?
   

AlecK
May 07 2013 09:39

You are adding 2 plus 2 and getting 5.

The statement in ESR 24 that an RCD is electrically unsafe if it trips outside the times does NOT mean we as installers have to test for that when installing.

those trip times can be taken for granted for new RCDs, same as tripping on DC can be taken for granted if it's marked as type A.

The tests for that are part of meeting the RCD Standard, which is set in Wiring Rules 2.6.2.2.

The test we do in Section 8 is NOT to test that the RCD meets Standard - our simple field-test gear can't do that, you'd need a lab full of calibrated equipment.

The test in 8.3.10.2 is to show that we have connected the RCD correctly. The task of Section 8 is not finding faulty fittings (RCDs, in his case); it's finding faulty wiring.

have a look at 8.3.10.3; which tells you what the required result of the test is.
There's nothing there about meeting trip times. Instead it tells you that the RCD must disconnect the supply to the circuit.


It doesn't matter whether you use an RCD tester (which might be a simple resistor), or whether you use the integral test button; because what you need to do is prove that BOTH poles (all four for 3-phase) go open circuit, and that there is NO connection whatsoever between the line and load sides.

so the fact that when you push the button (or use your tester) the RCD handle clicks to the "off" position means NOTHING. You have to get out you ohm meter, or (easier) your volt meter, and PROVE DISCONNECTION OF ALL POLES.
If you don't do that, you haven't done the test.

I repeat, section 8 is about testing OUR work; it's NOT about testing products.
ESR 65, and new ESR 63, tell you that PEW must be tested; not that fittings must be tested.

So if we can take trip times for granted, why does ESR 24 bother to mention them at all?

Maybe partly because if you're installing to Part 1, you don't have that reference in 2.6.2.2 to the RCD Standard.
And maybe partly so they apply when working under ECP 51.
Maybe for other reasons. I'm not inside the head of the NZ Regulators.

However I am part of the team that writes the joint AS/NZS Wiring Rules; and while we're not infallible we do have reasons for what we put in them. Which is all rather a waste of time when so many don't bother to actually read what we write.

-------

In NZ, RCDs are DMRAs, so SDoC required.
In fact, they are also DHRAs, Approval required.
But because they are DMRAs, we as suppliers should have SDoCs for the RCDs we supply.
And from 1 July, we as installers will have to attach copies of those SDoCs to our CoCs.


   

Blair
May 07 2013 10:28

Not to nitpick AlecK but
Volot meter cannot test both active conductors have been disconnected. It can only test the pahes.
The ohm meter is the only meter capable of testing both active conductors have been disconnected.
Also the more complete RCD testers can measure the time it takes to disconnect and we do need to prove the RCD has tripped in under that time.
Lastly just last week I had a 2 pole RCD that failed to trip at all so we do need to prove that they are working as designed.
   

AlecK
May 07 2013 12:24

Yes you can use a volt meter - and it's quicker. It saves turning off supply so that ohms tests are safe.

quick test sequence (or a 2-pole RCD):

1 test line side = 230 V
push test button (or operate RCD tester if you want to waste time connecting it to the subcircuit cabling)
2 test load side = 0 V (shows one or both are open-circuit)
3 test Line A to Load N = 0V; if 230 v then N pole has not opened.
4 test Line N to load A = 0 V; if 230V then A pole has not opened.

So there is more than one way to skin this particular cat.

I know a good RCD tester can measure the trip time, and that can be a useful diagnostic function.

But it is NOT required as part of mandatory tests for compliance of PEW.

Read the Notes.
Note 2: connection of test equipment to fixed wiring shall be restricted to connections made by 3-pin plug into a socket.
Making it difficult if the RCD is only protecting lighting
Note 3 a suitable test could be performed using a test lug with a resistor between active and earth.


While there are occasional faulty RCDs, the purpose of testing is to identify faulty installation work.


Testing the trip time is an optional extra, NOT a required test. I don't knock those who do it, in fact I usually do it myself; but it's important to recognise what is and isn't mandatory.

A statement in ESRs that a particular failure = electrically unsafe does NOT, by itself, impose any obligation to perform testing. The obligation to perform testing is imposed separately, and only refers to testing of PEW, not to testing fittings.

Those fittings are deemed safe if they comply with the Standard [ESR 80] so all we need in order to certify "safe and compliant" is evidence of compliance.
We are NOT obliged to undertake testing to check compliance with manufacturing Standards, and field tests - no matter how good your tester or how recently calibrated - CANNOT test to the required level.

if you use 2nd-hand RCDs, then there's no "deemed safe" so there's an arguable case that trip-time tests should be done to provide some evidence of safety. That's evidence, NOT proof. And it's a long way short of "must test".

The ONLY thing that's automatically acceptable as proof of compliance with Standards is a test report from a lab, and then only if there's no evidence against [ESR 81].


   

AC Guy
May 07 2013 12:36

I wonder if a lawyer would share your veiw Alec.
   

AlecK
May 07 2013 14:13

Lawyers take the view they are paid to take.
But they are not able to make words mean different things.

Some might say there's an implied requirement to test trip times. I don't agree, and even if true I think mere implications are far from good enough.
An obligation to do something - or not do something - has to be stated clearly. That's a fundamental requirement of Laws and Regulations; what's called natural justice.

So as long as my insurance will pay my lawyer to defend me, I'm happy with my interpretation.

If you agree with my interpretation, feel free to agree - but pay for some insurance just in case.

If you think my interpretation is wrong, don't follow it.
   

The Don
May 08 2013 12:17

Brian , I'm with Alexk on this one , you have correctly identified the rule that requires us to test RCd's and the rule explains the requiements for NZ.
So apart from specific areas such as Medical etc where timed testing etc is specified then the push button test is all that is required .
Don't forget the regulations are not just directed at us sparkys but also manufacturers , so reg 24 is making a statement about RCD's those conditions must be meet before the RCd is allowed to be sold , and the RCD should have a SDOC to prove the standard it is built two . No part of 24 mandates we have to prove it meet those requirements.
Another way of looking at it which may assist people in understanding, is if you install a 4.5 KVA MCB , do you do a test on it to insure it will break up to 4500 amps in the appriopriate time frame , ( answer, HELL NO , you assume what you have been supplied meets the requirements of the standard its built two .
However the above aside the is no harm done by doing the tests avaiable using an RCD tester as this is also an option under Rule 8.3.10.2
   

Russ
May 08 2013 12:39

Seems contradictory to me..
we have a clear definition of what a safe RCD is and we certify an newly installed RCD as being safe, yet the rules say we only have to press the test button which does not come close to proving that the definition of a safe RCD has been meet.
   

Blair
May 08 2013 13:46

My only comment/question would be if you install a new RCCD for a powerpoint and dont test it and it is faulty and breaks at 0.6 seconds a) how would you know
b) who gets the blame sparky or supplier

Remember no electronic product is ever perfect and 1 in a thousand mail fail to some level. Another sparky or inspector is called after some problem and finds the RCD doesnt operate in time? who gets big stick whack.
   

The Don
May 08 2013 14:35

@ Russ , I understand your thinking but really we are not certifying the RCD is safe in relation to reg 24 at all , we don't have to , what we are certifying is that we have installed it correctly and it operates as designed ( when push button test is carried out ) and we should also check both poles do actually open ) its the manufacturer who is certifying that it meets reg 24 by having a SDOC which states the standard it is made to.

@ Blair If you carry out the push button test then you have meet your responsibilty end of story .

Its good to see though that both you and Russ take your responsiblity seriously and good on you if you go the extra mile and carry out more intense testing and I wouldn't advocate for one minute that you don't do it and I don't think Alexk is suggesting that either but just simply stating the fact that its not mandatory.
   

Brian W
May 08 2013 17:06

Ok, I get all of that, and to the larger extent, agree with you Don, however I can't help thinking that there's some ambiguity in clause 1 of Reg 24 where it talks about safety of RCD's being 'used' as apposed to supplied, or sold. The use of the word 'used' could be taken to imply that as we are 'using' RCD's in the installation, we are obligated to ensure they operate within the parameters set in Reg 24, and are deemed to be safe as per the reg.
   

AlecK
May 08 2013 18:28

It's not polite to say so, but ES simply don't have enough competent people to do everything right.

Som eof the apparent silliness may be so they can change things more easily later
Eg where new ESR 65 mentions CoC for maintenance" yet ESR 6A says it's Low risk and so no CoC.
but simply by altering 6A to take some or all maintenance out of "low risk", hose seemingly pointless words in 65 would suddenly mean quite a lot.
They may be that clever - or that vious.

Or maybe different sections were put together by several of their most junior people, to fit a broad "outline of intent" (thatitself kept changing as they went), and no-one had time to do proper editing job.

One thing we do know is the senior technical advisor also has to cover the gas Regs and now the mining Regs as well.
so he won't have time for crossing eyes & dotting tees.

It would be nice if it was completely tidy, but it aint; and we have to do the best we can with it. Sometimes we'll be wrong.

Unlike some, I have never felt that either ES or EWRB was out to get me.

I am quite sure that - for Part 2 PEW - if I have tested as per section 8 I have complied with the testing obligation of ESR 65 (new 63), and with SDoC I have "deemed safe" for a new RCD. In fact after 1 July I can rely on that SDoC whereas right now it's only "evidence" of compliance

That's good enough for me to declare my work "installation safe; work i.a.w act & Regs" Or in the new words "safely & lawfully done".

Though like TheDon I support anyone who wants to do more than the minimum testing, and usually (always for non-new) do the trip time test myself.


One thing with testing RCDs, particularly 3-phase; whatever you have connected to them can upset the test, so tsometimes the only way to get a clean test is to disconnect everything except the tester. After re-connecting the subcircuit, it pays to do a push-button test TO PROVE THAT YOU HAVE CONNECTED CORRECTLY (which was after all the main point).
   

BillBloggs
Sep 14 2017 00:03

@AlecK

By saying "test the wiring" you're referring to supply wiring right? Because a test button will operate whether or not load is connected.
So if you're wondering whether or not you connected the red wire to the "A" terminal and the black wire to the "N" terminal you may want to perform every test available to ensure you haven't made any more errors!

   

AlecK
Sep 14 2017 10:34

The intent - in fact the clearly stated purpose - of ALL inspection & testing in section 8 is to confirm that our work complies. NONE of it is about product compliance. Check 8.1.2 para 2: "To confirm that the requirements of this Standard have been met".

For RCDs, 8.3.10.2 says: "to verify that the RCD operates to disconnect the designated circuit". The note advising that use of a plug + resistor is a "suitable" test makes it even clearer that "test equipment" does NOT need to be capable of measuring trip times.

   

AlecK
Sep 14 2017 10:35

"Forbidden" error prevents rest of post
   

BillBloggs
Sep 14 2017 13:27

From a liability perspective, how would one prove once leaving site that the push button test has been performed ensuring compliance of the work completed to standards?
   

AlecK
Sep 14 2017 14:36

Same as for any other test: record your results.
Not that any kind of record is absolute proof of having done any test, but it's the best evidence you'll get short of filming yourself doing the test.
So it's equally valid to choose not to.

The key aspect is that you issue a CoC that states the work has been done "lawfully and safely" (statement required on every CoC by ESR 66); and that automatically includes that required testing has been done. If any required testing wasn't done, the statement is automatically false.

since a CoC is a legal declaration, anyone alleging testing wasn't done would need evidence to back their assertion.
After which it comes down to who is more credible. Recording results may assist with credibility - but may not help you much if things are found not to be right.
   

SparkyJoe
Sep 15 2017 11:11

Take your multi function tester, Set it to auto rcd test, Do the tests, (1/2, full, x5) on both sides of the wave, record the highest result for x1 and x5. Write it down on a test sheet.

Fuck just pressing the button, your book needs updating lol
   

rarrar
Sep 15 2017 11:18

hehehehe you said fuck!
   

SparkyJoe
Sep 15 2017 11:26

I can also say "Massive ballbag"
   

AlecK
Sep 15 2017 14:39

SparkyJoe:
After doing all those (extra)tests, you still haven't done what you are required to do.
Which is to check that all poles are disconnected when the RCD trips.

You're spending time proving (or trying to) that the RCD complies with product Standards - something you don't have to prove; but instead are entitled to rely on the SDoC for. Your choice.
But at the same time you're failing to prove what wiring rules & ESRs require you to: that your work is compliant.

There has been at least one death in past year by incorrect installation of RCD combined with failure to test. Available info indicates (among other things) there was a crossed connection with another circuit downstream of the RCD, so even when it operated the circuit wasn't disconnected.
Also incorrect line / load connections resulted in the pushbutton test circuit being burnt out.

Routine testing is important for ongoing protection; and just leaving them sitting there can result in them not working when they should. We should be encouraging our customers to "push the button(s)" at daylight savings changeover time (like checking smoke alarm batteries.)
   

Sarmajor
Sep 15 2017 17:47

It would appear that Sparkyjoe has been sucked in by the people who sell multi function testers.

The book says push the test button and confirm that the device has disconnected all conductors. Nothing about trip time in section 8 of AS/NZS3000:2007.

As long as he product has an SDOC the manufacturer wears it if the unit does not trip within the required times, not the installer, as long as the installer tests to the requirements AS/NZS3000:2007 section 8.3.10.2 in New Zealand.

Most important is section 8.3.10.3 which gives the required result for the RCD test. No mention of time in there.

There is nothing wrong with AlecK's book or mine.

The more correct place for testing of RCD operating times by electricians is when testing portable RCD's.

ESR 24 is a higher level requirement and is aimed at suppliers, manufacturers and specifies. Selection and installation of the incorrect (but fully functional) RCD could result in an unsafe installation. For example the wrong 10ma RCD in a patient treatment area would be unsafe.
   

pluto
Sep 15 2017 19:30

Perhaps a few more points to add to the mix, in no particular order of importance.

1. the RCD Active connected correctly, the active supply to the active "mains" terminal(s) if mzrked.

2. the RCD neutral is connected correctly, the supply to the neutral "mains" terminals if mzrked.

3. The load active and neutral load cables are correctly connected to the load termunals.

4. The correct type ogf RCD is used, type A form a minimum.

5. If continuous d.c. is flowing to the load exceeding 6 mA constant current flws have to use type F or B.

Just a few more points to consider when installating RCDs and there are more to come!


   

SparkyJoe
Sep 15 2017 22:52

Sorry Sarmajor Im an english spark working over here, I honestly believe that if you dont have a insulation resistance / earth loop / rcd tester be as it is an all in one unit or as a multifunction. you arnt testing properly and its only a matter of time before you hurt someone.
   

Sarmajor
Sep 16 2017 08:29

Sparkyjoe, I fear the bigger problem is caused by the people who incorrectly assume that just because they plugged their RCD tester into a power point and pressed the test button they have complied with the requirements of section 8.3.10.2. Unfortunately they have not completed a satisfactory test of the RCD as required by section 8. They have only confirmed that at least 1 pole of a single phase RCD has opened, not both.

They should have confirmed all of Plutos points long before getting to RCD testing. Except for point 5 they are all visual or volt / ohm meter testable items.

But a bit of testing is better than no testing which I fear is the more common practice, of course no one who visits this forum would be guilty of that.
   

pluto
Sep 16 2017 10:44

Sarmajor Sep 16 2017 08:29
Your comment (part only)

They should have confirmed all of Plutos points long before getting to RCD testing. Except for point 5 they are all visual or volt / ohm meter testable items.

My comment

How many would done this checking before testing?

Not many would be aware of these additional requirements are part of the correct operation of RCDs, however, the upcoming amendment 1 of AS/NZS 3000:2017 will have the necessary information, more to learn about the application of RCDs.
   

Sarmajor
Sep 16 2017 12:28

Pluto,
You would hope that because they have a current plastic card and are therefore deemed to be competent the simple things like visually inspecting their work to ensure that it at least looks to be correct would be a logical first step.

Even a simple read through of section 8 should give electricians the idea that visual checking should be the first thing to do before they even start testing.

Section 8.1.2 shall be inspected and tested.
Section 8.2.1 a visual inspection shall be made.
Section 8.3.1 tests in accordance with 8.3.3 shall be carried out.

I have been to sites to do high risk mains inspections and failed the site before even pulling a test instrument out of the vehicle because I could see basic things wrong and there was no electrician on site to fix them.

If it doesn't look right it most likely isn't right.