I am confused over the wording of Regulation 411.1

[John Lundrigan]

Regulation 411.1 states that:
Automatic disconnection of supply is a protective measure in which:
(i) basic protection is provided by basic insulation of live parts or by barriers or enclosures, in accordance with Section 416, and
(ii) fault protection is provided by protective earthing, protective equipotential bonding and automatic disconnection in case of a fault, in accordance with Regulations 411.3 to 6.

I understood protection against electric shock to be in two categories - (i) protection in no-fault conditions which is provided by stopping persons and livestock actually touching live conductors and (ii) if a conductive part becomes live through a fault then somehow disconnect to ensure that the duration of current flow is limited, mainly through automatic. disconnection.

But Regulation 411.1 seems to imply that Automatic Disconnection of Supply itself includes BOTH basic protection as well as automatic disconnection. Surely Automatic Disconnection involves only (ii)

Jonel

 

[AJshep]

Automatic disconnection of supply or ADS does need to satisfy both points i and ii.

It used to be called Earth Equipment bonding & automatic disconnection of supply or EEBADS but apparently people didn't understand it so they changed it to ADS for the simply folk.

 

[Deleted member 26818]

Equipotential Earth Bonding & Automatic Disconection of Supply.

 

[AJshep]

I told you the simple folk didn't understand it !

Damm autocorrect.

 

[Deleted member 26818]

Have had to say Equipotential out loud in the past, so that Tutors have been able to pronounce it correctly

 

[John Lundrigan]

I understand but if ADS is being defined as requiring (i) and (ii) then why is the phrase ADS used again in (ii), This then becomes recursive and includes basic protection again. So, I feel that the semantics of the definition are confusing.

Jonel

 

[Simonslimline]

ADS is a protective measure which is the combination of two protective provisions, Basic protection and fault protection.

ADS requires,

Basic protection provided by insulation of live parts or by barriers or enclosures; and fault protection provided by:

Earthing, protective equipotential bonding; and automatic disconnection in case of a fault.

 

[Deleted member 26818]

I suppose it can seem a little confusing.
Just about every protective measure includes basic insulation of live parts.
So what they are saying, is ADS is automatic Disconnection of Supply with basic insulation.
Protective Equipotential bonding is not strictly necessary.

 

[Simonslimline]

worth a read.

Protection against shock - IET Electrical - http://electrical.------.org/wiring-matters/52/shock-protection/index.cfm

 

[John Lundrigan]

I understand all of what you refer to, that was not the point of my original post. Automatic disconnection is being defined by on the very first line of Regulation 411.1. If Protective Equipotential bonding is not strictly necessary then what regulation 411.1 is really saying is that Automatic Disconnection of supply is provided by automatic disconnection!

That was all my original post was trying to make clear.

Thanks everybody for the replies. I just have a little difficulty with the logic of this particular Regulation. I understand the aim of the regulation though and do not disagree with any replies that I have had.

Thanks

jonel

 

[happysteve]

I think I get what you're on about: semantics.

Think of "ADS" as a label. Replace it with something else of your choosing: "Large green chicken," for instance. So:

Large green chicken is a protective measure in which:
(i) basic protection is provided by basic insulation of live parts or by barriers or enclosures, in accordance with Section 416, and
(ii) fault protection is provided by protective earthing, protective equipotential bonding and automatic disconnection in case of a fault, in accordance with Regulations 411.3 to 6.​

As mentioned above, the label used to be EEBADS which was too much of a mouthful (and too similar to "Ee bah gum" to avoid confusion in all circumstances) so they shortened it to ADS.

Should've gone with LGC in my opinion, but hey.

 

[Wilko]

... Should've gone with LGC in my opinion, but hey.

Mmmm - large green chicken curry

 

[John Lundrigan]

Well, to continue you analogy :-

Large green chicken is a protective measure in which:
(i) basic protection is provided by basic insulation of live parts or by barriers or enclosures, in accordance with Section 416, and
(ii) fault protection is provided by protective earthing, protective equipotential bonding and large green chicken in case of a fault, in accordance with Regulations 411.3 to 6.

This was all I meant. But I will close on this now because I seem to be upsetting people and I had no intention of doing such a thing.

Thank you all

Jonel

 

[AJshep]

Your not upsetting anyone mate, it is a bit confusing as it sounds like it contradicts itself.

Automatic disconnection of supply is a technical term we as electricians use that is what the opening statement of the regulation is getting at by calling it a protective measure.
Your mainly see this written on Electrical test certificates abbreviated as ADS.
It could be called anything though like "Large green Chicken"

So In your analogy

Swap Large green Chicken back to automatic disconnection of supply in point (ii) but leave it as Large green Chicken in the opening paragraph.

 

[happysteve]

You're honestly not upsetting anyone (not me, anyway).