Adding a Fuse Spur on to a Consumer Unit Circuit

[RDB85]

I’ve had a disagreement with one of the Engineers in work. So we are doing an install. Installing an Intruder Alarm. Rather than go with my suggestion of coming off a Socket and adding in the Fuse Spur as he’s been doing it 15 years it’s now going next to the Consumer Unit. Which at a guess is 20 years old. He said it’s fine to just add in a circuit to an existing circuit.

Myself personally I’m dead against it. He’s not a qualified electrician. Thoughts?

 

[James]

I can think of one guy who works for a well known alarm company, whose knowledge of electrical systems is incredible (not simply alarms). Unfortunately he is a one off and his colleagues conform to my earlier, lazy stereotype.

Same here, good ones are hard to find in any trade.

 

[ipf]

Alarm engineers is a loose term. Anyone can program an alarm. I love the arrogance they have about them sometimes

Hence my regular use of the word 'engineer' in inverted commas, certainly in such instances.
Use of a quite special word by the 'not so special'.

 

[RDB85]

One of the ones today was it’s okay for our alarm panel to work from a switched FCU to a unswitched FCU as long as it’s spurred from the live side!

I just didn’t have the heart to tell him that he was talking absolute rubbish.

 

[nicebutdim]

One of the ones today was it’s okay for our alarm panel to work from a switched FCU to a unswitched FCU as long as it’s spurred from the live side!

I just didn’t have the heart to tell him that he was talking absolute rubbish.

Extending or spurring from a circuit.

Am I missing something here?

 

[RDB85]

Extending or spurring from a circuit.

Am I missing something here?

Socket circuit has a switch fuse spur that then has our unswitched fuse spur added on to it. As far as I know you can’t do. I’m not sure what the spur from the live side even relates to.

 

[nicebutdim]

Is this a ring final circuit?

 

[RDB85]

Is this a ring final circuit?

Two radials by the looks of it.

 

[MJPD29]

Sounds like a spur from a spur to me? Should be from the load side of the original spur if it’s a ring

 

[nicebutdim]

Two radials by the looks of it.

FCU is supplied from two separate circuits? This is getting more complcated with each post.

 

[RDB85]

Sounds like a spur from a spur to me? Should be from the load side of the original spur if it’s a ring

Yes it’s a spur from a spur. Which I was always taught you couldn’t do.

 

[nicebutdim]

Yes it’s a spur from a spur. Which I was always taught you couldn’t do.

On a radial ciruit, this would simply be an extension of the circuit.

If it had been a ring you would be correct about 'spurring from a spur', but I doubt an alarm panel fused at 3A would trouble the supply cable.

I believe the latter would contravene BS7671, but shouldn't present any issue from an electrical perspective. I stand ready to be corrected

 

[RDB85]

No worries Tel. It’s been a while since I’ve had my head in Electrical Books since changing to Security.

 

[rewireIT]

I agree it shouldn't be added to a lighting circuit but why do you say not a ring circuit?

Howcomes? What's the difference electrically between adding a single pendant straight from the breaker on a lighting circuit and adding a single pendant to the end of the line?

 

[rewireIT]

So as you say neither of you are qualified electricians.

you are doing an electrical installation of a new circuit or maybe an alteration to an existing circuit.

If you are doing this for reward, i.e. it is a paid job, how on earth have you got insurance to trade doing work that you cant show competence in?

Who fills out the installation certificate?
how do you show compliance with the regs and how do you test and document it?

He said 'one of the engineers', i'm presuming there's more than just them two. Please OP for the love of God tell me there are other competent people at work???

 

[MJPD29]

Yes it’s a spur from a spur. Which I was always taught you couldn’t do.

On a radial circuit it doesn’t really make any difference. On a ring the second spur must be from the load side of the first fcu