RCD tests and EIC

[Theorysparky]

Just a quick question..

on duel RCD boards do you guys test every cct ????

the OSG only shows one x1 result per RCD

 

[green-hornet]

Yes I test each circuit the results will almost be the same, each rcd will give different times and each curcuit should disconnect in the given times.

 

[Andy™]

i test each RCD from a circuit and not from all

 

[Theorysparky]

Thats interesting !!!

 

[Andy™]

as GH says, a test from each circuit may give slightly different trip times, but the regs do state test shold be done as near to RCD as possible, so you could easily test at the RCD terminals, then all results will definitely be the same

 

[steptoe]

I test the RCD.

NOT the circuity, the Zs proves the circuit.

 

[dan.]

agree with steps

 

[ianmacd]

I specifically asked ELECSA about that as I tested once per RCD and they said that was correct.

 

[The Godfather]

I test the RCD.NOT the circuity, the Zs proves the circuit.

Which would be my boys way of thinking.

Don & His Boys

 

[green-hornet]

However each circuit has a column relating to the rcd type and disconnection times, your proposals are to now fill each column as N/A ?

If so the electrical installation certificates will have to be reprinted with all the columns removed, and in its place two columns one for each RCD .

I would suggest you get back on the line to Elesca and verify why such a statement was made and why.

I still do every circuit but all my certs are fully filled and not part filled.

 

[The Godfather]

However each circuit has a column relating to the rcd type and disconnection times, your proposals are to now fill each column as N/A ?If so the electrical installation certificates will have to be reprinted with all the columns removed, and in its place two columns one for each RCD .

I would suggest you get back on the line to Elesca and verify why such a statement was made and why.

I still do every circuit but all my certs are fully filled and not part filled.

Well the Don, cannot agree with your line of thinking here.

On a 17th edition CU, we have 2 RCD's connected to 2 banks of circuits. In a newly tested installation, with no equipment etc connected and with all circuits exceeding the minimum requirements of BS7671 testing (Zs, IR, R1 + R2, functional testing etc).

And verified each circuit is on which bank, then surely testing of the RCD at the CU (and or at individual circuit point) is sufficient.

And then the RCD times applied to ALL circuits on the relevant bank.

The Godfather

 

[NozSpark]

I use the BS forms, what I do is test each RCD in isolation as Steps and the Don do. In the RCD column I put a tick and note the RCD results in the comments column...

 

[green-hornet]

I would agree to a point, however each circuit will trip the rcd at differing times.

Whilst a Zs would give the fault loop and an indication that the rcd will trip within the given times, I like to find out by testing which circuit under fault conditions at point of use will give the maximum trip time possible.

I never like to replicate figures, it just indicates that the test has not been carried out, and would not reflect the actual trip time of the rcd for that circuit.

 

[The Godfather]

Let's consider one other aspect here:

The moment the installation becomes populated with domestic appliances (say for example), we introduce leakage (which increases with the age of the product or because of it's particular function (washing machine for example)).

So in reality the RCD may will trip at a different time or threshold depending on what is connected/operational at the time of a fault.

The Godfather

 

[The Godfather]

I would agree to a point, however each circuit will trip the rcd at differing times.Whilst a Zs would give the fault loop and an indication that the rcd will trip within the given times, I like to find out by testing which circuit under fault conditions at point of use will give the maximum trip time possible.

I never like to replicate figures, it just indicates that the test has not been carried out, and would not reflect the actual trip time of the rcd for that circuit.

But 30mA & 150mA testing are hardly going to be influenced by a 0.3ohms or 1ohms circuits loading (causing a variation)??

Green Hornet, I would be interested to know what variation you have recorded on some of your installations?

Don

 

[green-hornet]

To be honest very little, however I have always recorded the highest readings I have ever come across, I test every socket on a ring, every light, every point on all circuits to find the highest reading I can, which I then record.

Its amazing what little problems you can find this way, even on a new install.

Which again is why when doing rcd testing I always search for the highest reading I can get, which involves testing all circuits, and writing down my findings, may take longer to test but ist something I have always done, and will continue to do.

If there is a space for a test result I like to fill it with the test result I have recorded.

I agree the differences may be minor even negligable but I walk away knowing I have recorded the highest value. Its just habit I suppose, see a box and fill it !

 

[The Godfather]

To be honest very little..

If you have the time and feel comfortable with your methods, then who am I (or anyone else for that matter) to pass criticism.

But you have commented there is little difference.

The Godfather

 

[SPECIAL LOCATION]

Page 91 On Site Guide,

RCD's General test procedure:-

The test are made on the load side of the RCD, as near as practicable to its point of installation and between the line conductor of the protected circuit and the associated CPC. The load supplied should be disconnected during the test.

REMEMBER

aren't we trying to test the RCD, to ensure it meets the specification, NOT the circuit?

All circuits that are connected to that RCD will have the same RCD operating time figures written in.

Just as with an old 16th ed split load CU

If you had a circuit that had a 10ma leakage somewhere along the cable or at an accessory still connected...

It could mess up some of your tests, e.g faster response or apparent tripping on the x1/2 scale.

Resistors in parallel divide the current but keep same volts across them

Resistors in series divide the voltage but keep the same current through them

IF the RCD has reached 30ma.. then surely further along the cable..

which is adding series resistance the 30ma will still be the same current flowing?

OR...........

shall I go and put me pants on my head? ?:|

 

[SPECIAL LOCATION]

I test the RCD.NOT the circuity, the Zs proves the circuit.

ConcurApplaud Smiley

 

[SPECIAL LOCATION]

agree with steps

and I agree with Dan and Steps!

Guiness Drink

good men both of em IMHO!