Struggled with this one

[rich3009]

Where the measure of automatic disconnection is employed, fault protection may be provided by
1. Protective earthing only
2. Protective equipotential bonding only
3. Protective earthing and protective equipotential bonding
4. Electrical separation

 

[rich3009]

I answered with 3 but the answer was 4 must be an error

 

[rich3009]

Is the fact that basic protection is not covered, but they clearly state fault 411.1 reg

 

[johnduffell]

I think 4 is the only one with a chance of working, bonding and earthing wouldn't work without ADS, need some way to disconnect the supply.
Separation would work if it puts things far enough apart there's no chance of a fault eg electricity pylons, although i doubt it's common in domestic.

 

[rich3009]

You are getting mixed up with placing out of reach, separation means via a transformer (electrical separation)

 

[Wilko]

I think the ans should be 3 too, as per 411.1 ii .

 

[telectrix]

i'd say#1 is the answer. some would argue #3, but bonding is not required for fault protection. bonding is there to prevent electric shock when in contact with both an exposed conductive part and a bonded service ( under fault conditions).

 

[Deleted member 26818]

This is one of the instances where BS7671 needs to be sorted out. Changing from EEBADS to ADS was a joke.
Both EEBADS and ADS are protective protective measures which according to BS7671 require both basic protection and fault protection.
Basic protection is provided by basic insulation of live parts, barriers, enclosures, obstacles or by placing out of reach.
Fault protection is provided by protective earthing, protective equipotential bonding and ADS.

So for the question if the protective measure ADS is being used, there should already be in place protective earthing and protective equipotential bonding. That’s answers 1, 2 and 3 out of the way.
Other measures for providing fault protection are:
(i) SELV
(ii) PELV
(iii) FELV
(iv) double or reinforced insulation and
(v) electrical separation.

 

[rich3009]

Then you would be in breach of 411.1 in answer to previous post above

 

[rich3009]

all told it's another bloody awful question, plus the answer refers to 411.1 as the source.

 

[Deleted member 26818]

411.1 is just a description of a particular protective measure, there’s no requirement to provide that particular protective measure.
Also, installations can and do have more than one protective measure.

 

[rich3009]

Totally understand that, just seems a very weird question

 

[AJshep]

I would have put 3 but after reading the response by spinlondon it makes a sense.
I hate these questions, I personally think this question should be worded differently maybe mention ADS in the question to make it more clear.

Where the measure of "Automatic
Disconnection of Supply" is employed............

 

[rich3009]

Is as though they're trying to be clever would be better to ask what other methods could be included, but the way I read it is you have an RCD at the board and they are now asking how do you create fault protection for your circuit, which you have no idea about location of or what it's for

 

[Richard Burns]

I would say it is a bad question and they got the answer wrong.

The way I read the question is that a measure of automatic disconnection, not the protective measure "Automatic Disconnection of Supply", is in place what is needed to provide fault protection for this circuit.
Based on BS7671 the protective measure "Automatic Disconnection of Supply" has three parts listed under fault protection: protective earthing, equipotential bonding and automatic disconnection.
You have one in place and you need the other two to complete the requirements for ADS.
Answer 3.