Switched Live sleeving when looping at switch

[JohnW2]

I think you need to speak to 'controls engineers' to find out what work they do and are expected to do. They are constantly having to correct the work done by electricians.

That's very probably true, but I don't see the relevance...

... with respect to all concerned, this is surely getting silly? Simon posted what I presume was a 'tongue-in-cheek Friday-night comment' about how one might try to wriggle out of the regs by describing a circuit with a functional switch (light switch) as a 'control circuit'.

If we were to describe every circuit which had 'functional switching' as being a "control circuit", then that would not leave much which was not 'a control circuit', would it? - and that would remain true whether the functional switching was done by a manual switch, a time switch, a sensor-operated switch (thermostat, humidstat, pressure switch etc.), relay/contactor contacts or whatever.

To continue with Simon's recent example, my heating system here has several relays. I (and I suspect most people) would regard the circuitry (and conductors) supplying the relays' coils as "control", but would not dream of using that word to describe the circuits whose full load currents were switched by the relay contacts. I find it hard to believe that I am unusual, let alone unique, in thinking like that!

Kind Regards, John

 

[SUNRAY]

That's very probably true, but I don't see the relevance...

... with respect to all concerned, this is surely getting silly? Simon posted what I presume was a 'tongue-in-cheek Friday-night comment' about how one might try to wriggle out of the regs by describing a circuit with a functional switch (light switch) as a 'control circuit'.

If we were to describe every circuit which had 'functional switching' as being a "control circuit", then that would not leave much which was not 'a control circuit', would it? - and that would remain true whether the functional switching was done by a manual switch, a time switch, a sensor-operated switch (thermostat, humidstat, pressure switch etc.), relay/contactor contacts or whatever.

To continue with Simon's recent example, my heating system here has several relays. I (and I suspect most people) would regard the circuitry (and conductors) supplying the relays' coils as "control", but would not dream of using that word to describe the circuits whose full load currents were switched by the relay contacts. I find it hard to believe that I am unusual, let alone unique, in thinking like that!

Kind Regards, John

Domestic electrics and controls are 2 different topics, although they do become intertwined I would not call a SL a control circuit in a domestic situation. I would not particularly advocate marking the SL but sometimes it could help when a large number of cables come together and having worked on singles systems where SL's are a different colour (usually white, yellow or purple) it is nice in a larger switch plate to see the difference quickly.

As someone who has worked in the controls industry for the best part of 25 years, I'd say that everything after the time switch/programmer is classed as controls and TBH I would expect a schematic to be left showing wire colours and I believe they do not need to be sleeved brown (as mentioned in the regs), in fact the brown sleeves often inhibit faultfinding by obscurring the wire colours and taking up too much space especially in domestic central heating wiring centres (or whatever the particular manufacturer calls it).

And yes in order to get brand new circuits working I am one of those people who have to go round clearing up after electricians cock ups.

 

[SUNRAY]

That's very probably true, but I don't see the relevance...

... with respect to all concerned, this is surely getting silly? Simon posted what I presume was a 'tongue-in-cheek Friday-night comment' about how one might try to wriggle out of the regs by describing a circuit with a functional switch (light switch) as a 'control circuit'.

If we were to describe every circuit which had 'functional switching' as being a "control circuit", then that would not leave much which was not 'a control circuit', would it? - and that would remain true whether the functional switching was done by a manual switch, a time switch, a sensor-operated switch (thermostat, humidstat, pressure switch etc.), relay/contactor contacts or whatever.

To continue with Simon's recent example, my heating system here has several relays. I (and I suspect most people) would regard the circuitry (and conductors) supplying the relays' coils as "control", but would not dream of using that word to describe the circuits whose full load currents were switched by the relay contacts. I find it hard to believe that I am unusual, let alone unique, in thinking like that!

Kind Regards, John

Domestic electrics and controls are 2 different topics, although they do become intertwined I would not call a SL a control circuit in a domestic situation. I would not particularly advocate marking the SL but sometimes it could help when a large number of cables come together and having worked on singles systems where SL's are a different colour (usually white, yellow or purple) it is nice in a larger switch plate to see the difference quickly.

As someone who has worked in the controls industry for the best part of 25 years, I'd say that everything after the time switch/programmer is classed as controls and TBH I would expect a schematic to be left showing wire colours and I believe they do not need to be sleeved brown (as mentioned in the regs), in fact the brown sleeves often inhibit faultfinding by obscurring the wire colours and taking up too much space especially in domestic central heating wiring centres (or whatever the particular manufacturer calls it).

And yes in order to get brand new circuits working I am one of those people who have to go round clearing up after electricians cock ups.

 

[JohnW2]

Domestic electrics and controls are 2 different topics, although they do become intertwined I would not call a SL a control circuit in a domestic situation.

Quite so - as I've said, same here.

I would not particularly advocate marking the SL but sometimes it could help when a large number of cables come together ...

Exactly. As I've said, I do it very rarely (and, when I do, in situations such as you describe) and have merely explained how I personally do it on those rare occasions that I do.

As someone who has worked in the controls industry for the best part of 25 years, I'd say that everything after the time switch/programmer is classed as controls ....

Do you really mean "after"? If so, do you mean that you would describe the feed (from timeswitch or programmer) to, say, an immersion heater as being a 'control circuit'??

... in fact the brown sleeves often inhibit faultfinding by obscurring the wire colours and taking up too much space especially in domestic central heating wiring centres ...

Indeed - and that's why, in such situations, I always use relatively short lengths of over-sleeving ('rings'), which seems enough to satisfy BS7671, always making sure that plenty of the underlying colour is still visible.

Kind Regards, John

 

[SimonH2]

I think we're in danger of trying to categorise all horses as either "true white" or "true black" - while in reality they are rare (true white) or uncommon (true black), and most horses are various shades/patterns of other colours.
Now, if I throw in a wiring diagram :
EDIT: It's a mix of old and new colours with fixed wiring of various ages.

I assume that at least some of you will argue, black and white, no room for debate, that circuits 1, 2, 3, and 4 are all "power" circuits" and not one of them is a "control" circuit ? Personally, I would argue that all 4 of them are control circuits because they form the control system (with the timer and three stats as control elements) for the pump and boiler.
We get into a deep philosophical debate as to where the dividing line is between a functional switch and a control system - I don't believe there is a line, just a very large grey area. I believe that a light switch is a control system, albeit the simplest one possible, to one or more lights - and therefore the switched line for the light could be considered to be a "control" circuit. OK, that is rather pushing things
In the above diagram, I am confident to call that a control system and class the internal connections as control circuits - allowing the smaller minimum wire sizes (0.5mm² vs 1mm² for lighting or 1.5mm² for power, table 52.3) and the use of alternative wire colours (table 51).

One can always use numbers as permitted by 514.5.4

 

[JohnW2]

I assume that at least some of you will argue, black and white, no room for debate, that circuits 1, 2, 3, and 4 are all "power" circuits" and not one of them is a "control" circuit ? Personally, I would argue that all 4 of them are control circuits because they form the control system (with the timer and three stats as control elements) for the pump and boiler.

I think the problem may be in relation to the sense in which the word "circuit" is being used.

My view is that wiring which connects a power source to a load through one or more switches ('switching devices') is "a circuit" - and that the remains true whether that/those switches are manual ones, timeswitches, thermostats or anything else. The example you give is slightly complicated by the fact that there are two loads but if one forgets the pump then I would say that what you call 1, 2, 3 and 4 are all parts of one circuit (not four circuits) - which is simply a load supplied with power via four 'switching devices'.

Hence, contrary to what you suggest, I would not say that 1, 2, 3 & 4 were 'power circuits' (nor 'control circuits') - I would say that they were all parts of one circuit, which consisted of a load being supplied with power via a string of switching devices in series.

I suppose a clue is in the word - to my mind, a 'circuit' goes from L of the supply, via one or more switching devices then through the load and finally back to N of the supply.

Kind Regards, John

 

[SimonH2]

Yes, circuit wasn't the best choice of word.
Conductor doesn't sound right since they are (mostly) more than one conductor. Ditto wire.
Node ? Still doesn't sound right.
Back when I was designing circuits we'd talk about busses and lines - eg address bus, address line 0, etc. But given the use of the word "line" in current context that would be very confusing
Suggestions for what to call "the collection of wires connected to point 1" etc ?

PS - I'll post another diagram (or maybe 2) in a day or two that will make the distinction even harder.

 

[SUNRAY]

Quite so - as I've said, same here.
Do you really mean "after"? If so, do you mean that you would describe the feed (from timeswitch or programmer) to, say, an immersion heater as being a 'control circuit'??
Indeed - and that's why, in such situations, I always use relatively short lengths of over-sleeving ('rings'), which seems enough to satisfy BS7671, always making sure that plenty of the underlying colour is still visible.

Kind Regards, John

Yes I do mean after but My problem is I avoid domestic stuff and therefore have a different outlook than house bashers.
I'm accustomed to working with control panels containing many 'circuits' and each one of them is classed as 'control', the 'electricians' circuit will finish at the main isolator.

So yes an immersion heater on some sort of programming device, be it a time clock - thermostat - electronic controller - or a switch in the matrons office will be described as a control circuit. However domestically I'd probably only consider the link between the thermostat and element to be the controlled circuit and totally ignore the title.

Domestically I would only consider refering to control circuits for the more conplex arrangements, heating being the most obvious but with the amount of home automation now in use of the title is firmly expanding.

I think we're in danger of trying to categorise all horses as either "true white" or "true black" - while in reality they are rare (true white) or uncommon (true black), and most horses are various shades/patterns of other colours.
Now, if I throw in a wiring diagram :
EDIT: It's a mix of old and new colours with fixed wiring of various ages.

Within the rules of 'control' this fully acceptable to be installed this way and is within the rules of MI's

I assume that at least some of you will argue, black and white, no room for debate, that circuits 1, 2, 3, and 4 are all "power" circuits" and not one of them is a "control" circuit ? Personally, I would argue that all 4 of them are control circuits because they form the control system (with the timer and three stats as control elements) for the pump and boiler.

I'm on your side but would consider it to be '2 control circuits' max as there are only 2 devices being controlled. Realistically I'd be happy to call it one circuit with 4 controlling devices.

We get into a deep philosophical debate as to where the dividing line is between a functional switch and a control system - I don't believe there is a line, just a very large grey area.

again I'm with you but would place the demarkation (if there is one) at the isolator or the input to the time clock.

I believe that a light switch is a control system, albeit the simplest one possible, to one or more lights - and therefore the switched line for the light could be considered to be a "control" circuit. OK, that is rather pushing things

Agreed

In the above diagram, I am confident to call that a control system and class the internal connections as control circuits - allowing the smaller minimum wire sizes (0.5mm² vs 1mm² for lighting or 1.5mm² for power, table 52.3) and the use of alternative wire colours (table 51).

One can always use numbers as permitted by 514.5.4

Where is the minimum wire size specified? Light pendants are 0.5 or 0.75mm²

 

[SUNRAY]

With all of the comments I've made in this thread I must say that I'm not trying to categorise or criticise in any way, so far I have some agreement with most of the comments made by others

 

[JohnW2]

Yes, circuit wasn't the best choice of word. Conductor doesn't sound right since they are (mostly) more than one conductor. Ditto wire. Node ? Still doesn't sound right. .... Suggestions for what to call "the collection of wires connected to point 1" etc ?

I'm somewhat struggling to understand why, in the context we're discussing, there is any useful purpose in trying to find a word to describe a particular conductor/wire/whatever (collection of conductors/wires/whatever) within a 'circuit' (in the usual electrical/BS7671 sense). Consider the simplest situation - which is, after all, the one which started this 'side discussion' ...

We can agree that 1 is "Line/Live" and that 3 is "Neutral". One can (and we do) call 2 a "Switched Line/Live" but, beyond that, I see no purpose on thinking of it as being different from any other part of the circuit. When things become more complicated ...

... I wonder which of the numbered items you would like to call "control <whatevers>", even if we could think of a suitable word? By analogy with the simple suggestion, I suspect that you would like to call everything other than 1 and 8 as "control <whatevers>" - is that the case and, if so what purpose does that serve.

Dragging this discussion back onto topic, the "loophole" which it was suggested might allow BS7671-compliant yellow identification of some of the conductors (e.g. in the above two examples) related to line conductors in control circuits - and I would suggest that nothing in either of the two examples above is, or contains, a "control circuit".

Kind Regards, John

 

[JohnW2]

Yes I do mean after but My problem is I avoid domestic stuff and therefore have a different outlook than house bashers. I'm accustomed to working with control panels containing many 'circuits' and each one of them is classed as 'control', the 'electricians' circuit will finish at the main isolator.

In a similar fashion as I responded to Simon, I think there may again be confusion resulting from the word "circuit" - which does have a variety of meanings. You, I think, are using 'control circuit' more in the sense of 'control circuitry', just as one might talk, in electronics, about an "amplifier {or whatever} circuit" - i.e. collection of inter-connected and/or inter-related components which, together performed some 'controlling' function - but which aren't necessarily 'a circuit' in the usual sense.

I'm not attempting to challenge the terminology as used in your profession, but what I am suggesting is that when BS7671 talks about a "control circuit" it is not talking about any circuit which supplies power to a load via some functional 'switching device(s)'. As you go on to say ....

So yes an immersion heater on some sort of programming device, be it a time clock - thermostat - electronic controller - or a switch in the matrons office will be described as a control circuit.

This is where I start struggling a bit since, as I've said before, that means that anything which includes any functional switching (whether manual or otherwise) would be a "control circuit" - and I really don't think that many people, whether electricians or otherwise, (or BS7671) would describe an immersion circuit or a lighting circuit etc. etc. as a "controll circuit", would they?

Kind Regards, John

 

[SUNRAY]

In a similar fashion as I responded to Simon, I think there may again be confusion resulting from the word "circuit" - which does have a variety of meanings. You, I think, are using 'control circuit' more in the sense of 'control circuitry', just as one might talk, in electronics, about an "amplifier {or whatever} circuit" - i.e. collection of inter-connected and/or inter-related components which, together performed some 'controlling' function - but which aren't necessarily 'a circuit' in the usual sense.

I'm not attempting to challenge the terminology as used in your profession, but what I am suggesting is that when BS7671 talks about a "control circuit" it is not talking about any circuit which supplies power to a load via some functional 'switching device(s)'. As you go on to say ....
This is where I start struggling a bit since, as I've said before, that means that anything which includes any functional switching (whether manual or otherwise) would be a "control circuit" - and I really don't think that many people, whether electricians or otherwise, (or BS7671) would describe an immersion circuit or a lighting circuit etc. etc. as a "controll circuit", would they?

Kind Regards, John

I think you're trying to over analyse John. As said earlier strictly speaking the immersion circuit a power circuit which contains a control device or two, now if if the clock and thermostat operated a contactor (a fairly regular format in a controls environment) there would be no difficulty in distinguishing between control and power, especially if they have their own feed and OCD, but in the absense of the contactor the lines are very blurred. In domestics I would tend to not describe this as a control circuit even though it still contains 2 (or 3 if you count the isolater) control devices.

In your circuit above I'd describe all of the 'live' wiring as the control and as there's naff all left I'd include the load too.

As I said the lines are very blurred.

If you go on a holiday, how much of it would you call the holiday?
From the time you start driving?
From loading the case into the car?
From starting to pack?
From booking the hotel?
From searching the internet?
From filling the tank?
Or from the wife starts nagging that she needs a holiday?

 

[SimonH2]

None of the above ...
From when I get back to work for a rest Only joking

In John's example, conductors 3-7 are definitely part of the control system. 2 is a bit more of a grey area. But if there were an isolator to the left of 1&8 then I'd include them too.

 

[bernardgreen]

All those circuits are power circuits. They carry power.

The power in those circuits is CONTROLLED by the settings of the various switches.

If the switch between 2 and 6 was a set of contacts on a relay then

circuits A B and C would be control circuits.

Simple rule, Any part of the system that is or by switching can be connected to the load is a power circuit,

 

[SUNRAY]

All those circuits are power circuits. They carry power.

The power in those circuits is CONTROLLED by the settings of the various switches.

If the switch between 2 and 6 was a set of contacts on a relay then

View attachment 169260

circuits A B and C would be control circuits.

Simple rule, Any part of the system that is or by switching can be connected to the load is a power circuit,

If the load was replaced by a CONTRACTOR and it powered the load then I could agree.
But even then it would still come under the jurisdiction of the controls engineer.
Everything within the control panel is quite deliberately kept locked away from untrained personel including 'qualified electricians' for 2main reasons, 1 so they don't get hurt (extremely common) and 2 so they don't break it (even more common).
I estimate half of my fault finding is putting right the damage caused by the previous guy(s) attempts at fixing a non existent fault.
A classic example of this was 'summer pumps' at a big Oxford Street store didn't run when the front door switch was on, the 'fully qualified electrician' ran a wire from the switch to the load side of the contactor which bypassed a whole line of interlocks, relay contacts, thermostat etc so they ran 27/7into a dead head.
This damaged the flow switch which shut down another part of the system which meant there was no hot water and the system had to be partially drained.