How many metres of electrica cable will i need approximately

[PlumbingandElectrics]

Hi we are a plumbing & electrics company but pricing a new job with electrics for 35 houses
Basically Central Heating Controls that are associated with the central heating.
our main Electrician is on holidays and he normally prices but have looked at his quotes and none have a break down. and this job has come up as a matter of urgency. can give a guess but would like to know for future
just basically stuck on the 1.5mm t&e, 3 core and earth and 1mm 3 core flex. How much of these approximately would be used in installing controls with 1 room stat, 1 wiring centre and 1 central heating time clock based on a small 3 bedroom bungalow or does anyone know where I could get a wiring plan that shows the wire used in these -
Many thanks for any help.

 

[EFLImpudence]

1mm² t+e will do - saved you 20% already.

 

[flameport]

A few hundred metres.

In any event, the cost of the cable will be an insignificant part of the price.

 

[winston1]

1mm² t+e will do - saved you 20% already.

1mm can only be used for lighting circuits. For non lighting applications such as CH controls 1.5mm has to be used. Mad I know but rules is rules.

 

[RF Lighting]

And the nonsense keeps coming...

 

[winston1]

And the nonsense keeps coming...

For f***s sake, stop being so rude and make yourself familiar with the regs. 1mm cable can only be used for lighting not anything else.

 

[Taylortwocities]

Well, you learn a new one every day. When I was taught my craft, the size of a cable was determined by the size of the protective device, environment, installation method, etc.

Not that I don't believe you, Winston, but please quote the regulation from BS7671 that backs up your assertion.

 

[JohnW2]

deleted : misread the post!

 

[JohnW2]

Well, you learn a new one every day. When I was taught my craft, the size of a cable was determined by the size of the protective device, environment, installation method, etc. ... Not that I don't believe you, Winston, but please quote the regulation from BS7671 that backs up your assertion.

Winston is talking about Table 52.3 in 524.1, but I think he's probably wrong. It does, indeed, say that the minimum CSA for 'power' circuits is 1.5mm² - but I don't think he noticed the bit that says that cables for 'signalling and control circuits' need only have a CSA of 0.5mm² !!

Kind Regards, John

 

[winston1]

Well, you learn a new one every day. When I was taught my craft, the size of a cable was determined by the size of the protective device, environment, installation method, etc. ... Not that I don't believe you, Winston, but please quote the regulation from BS7671 that backs up your assertion.

Winston is talking about Table 52.3 in 524.1, but I think he's probably wrong. It does, indeed, say that the minimum CSA for 'power' circuits is 1.5mm² - but I don't think he noticed the bit that says that cables for 'signalling and control circuits' need only have a CSA of 0.5mm² !!

Kind Regards, John

Indeed. The problem is that CH controls usually are part of power circuits switching the boiler, pump, etc.

 

[ban-all-sheds]

Winston is talking about Table 52.3 in 524.1, but I think he's probably wrong. It does, indeed, say that the minimum CSA for 'power' circuits is 1.5mm²

Is "power circuit" defined somewhere?

Or does it mean what it can only mean without any special definition, i.e. any circuit which provides electrical power to an accessory or current using appliance?

 

[ban-all-sheds]

The problem is that CH controls usually are part of power circuits switching the boiler, pump, etc.

You're very keen on definitions, winston. So what's a "power circuit"?

 

[JohnW2]

Indeed. The problem is that CH controls usually are part of power circuits switching the boiler, pump, etc.

So what do you reckon that a 'control' circuit is, then?

Kind Regards, John

 

[JohnW2]

Winston is talking about Table 52.3 in 524.1, but I think he's probably wrong. It does, indeed, say that the minimum CSA for 'power' circuits is 1.5mm²

Is "power circuit" defined somewhere?
Or does it mean what it can only mean without any special definition, i.e. any circuit which provides electrical power to an accessory or current using appliance?

Who knows?! (I refer you to our previous discussions about that question!). Given that the Table distinguishes between "Lighting", "Power" and "Signalling and Control" circuits, it clearly wasn't the intention of whoever wrote it that one should use the "what it can only mean" definition of yours above.

To add to the fun/confusion, winston has now raised the further question of "when is a control circuit a power circuit?"!

However, what you have written is playing into his hands, since it would support his assertion that 1.5mm² is the minimum CSA for wiring CH controls!

Kind Regards, John

 

[winston1]

Indeed. The problem is that CH controls usually are part of power circuits switching the boiler, pump, etc.

So what do you reckon that a 'control' circuit is, then?

Kind Regards, John

Difficult to say really. Wiring that does not directly switch 240v loads perhaps.