Ideal ICOS PCB - Worrying!

[OLLIE20]

Well, I wish I was there when he serviced the boiler, as im still baffled as to why he changed that 13A fuse to a 3A. he even made the point of saying “its amazing how many times I’ve had to change that fuse in other houses”

As an electrical designer, that original 13A fuse makes perfect sense to me. The cable feeding the boiler, from the spur is sufficiently sized to carry 16A, therefore, Ib< In< Iz. Thus the 13A CPD was safe, and coordinated with the 3A PCB CPD, allowing the CPD closest to the potential fault to fail first.

What he’s done is completely shafted the coordination between the upstream and downstream CPDs. So if a fault occurs on that cable feeding the boiler, you really want the fused spur to break first, but in reality either one will go.

please tell me im not going insane!

I usually bypass all that waorkinh out, although more than capable , i find it much quicker to give the MI's a check, generally on boilers it 3amp some are 5

 

[nickso]

change it to 5A if it makes you feel any better.[/quote


The fuse in the fused spur should be 3 amp. 5 and 13 amp fuses are the wrong size.

really? give me an argument that proves that statement.

 

[transam]

AsI understand it the rate of the fuse is the sum (total) of the current rating of all of the components used ??
( I am unable to take questions on this subject )



If I remember correctly some Keston boilers required a 5 amp rated fuse ? ( I think maybe ???)

 

[adlplumbing]

3a unless the mi say diffrently
and never looked for amp in their i have always assumed it was 2a
to be used
wonder if jackdike going to read this post

 

[Corgigrouch]

OP you may well be right that the cable fitted between the fused spur and internal connections will be good for 16 amp, but what about the internal wiring? from the connection onwards? Will this wiring be able to cope with 16 amps?... The cable fitted may well be what the installer happened to have with him. Don't forget that there will be wiring inside the boiler that is not protected by the fuse on the PCB and so relies on protection from the fuse in the fused spur..

 

[nickso]

OP you may well be right that the cable fitted between the fused spur and internal connections will be good for 16 amp, but what about the internal wiring? from the connection onwards? Will this wiring be able to cope with 16 amps?... The cable fitted may well be what the installer happened to have with him. Don't forget that there will be wiring inside the boiler that is not protected by the fuse on the PCB and so relies on protection from the fuse in the fused spur..

now thats probably the right answer.

 

[gdallas]

OP you may well be right that the cable fitted between the fused spur and internal connections will be good for 16 amp, but what about the internal wiring? from the connection onwards? Will this wiring be able to cope with 16 amps?... The cable fitted may well be what the installer happened to have with him. Don't forget that there will be wiring inside the boiler that is not protected by the fuse on the PCB and so relies on protection from the fuse in the fused spur..

now thats probably the right answer.

I cant even begin to tell you both how wrong you are!

lets get this straight before we go any further. the spur , protects the cable feeding the boiler...not the boiler...

All I will say is, read the 17th edition, and or any basic electrical principles textbooks.
I could quiet safely have wired in a 35mm2 cable feeding that boiler fused much higher than 13A! (Don’t have my current tables handy to quote a fuse size), 185mm2, even!!
You might want to read up on discrimination with downstream circuit protective devices...as what that BG engineer did was wrong, and I have since rectified this!
Ye im not a gas engineer, but I am an electrical engineer, BEng hons, electronic engineering. Member if IET.

 

[OLLIE20]

OP you may well be right that the cable fitted between the fused spur and internal connections will be good for 16 amp, but what about the internal wiring? from the connection onwards? Will this wiring be able to cope with 16 amps?... The cable fitted may well be what the installer happened to have with him. Don't forget that there will be wiring inside the boiler that is not protected by the fuse on the PCB and so relies on protection from the fuse in the fused spur..

now thats probably the right answer.

I cant even begin to tell you both how wrong you are!

lets get this straight before we go any further. the spur , protects the cable feeding the boiler...not the boiler...

All I will say is, read the 17th edition, and or any basic electrical principles textbooks.
I could quiet safely have wired in a 35mm2 cable feeding that boiler fused much higher than 13A! (Don’t have my current tables handy to quote a fuse size), 185mm2, even!!
You might want to read up on discrimination with downstream circuit protective devices...as what that BG engineer did was wrong, and I have since rectified this!
Ye im not a gas engineer, but I am an electrical engineer, BEng hons, electronic engineering. Member if IET.

I dont give a **** if your a rocket scientists, MI's state 3 amp then its 3 amp, you do something else and something goes wrong to do with it its your arse boy

 

[gdallas]

OP you may well be right that the cable fitted between the fused spur and internal connections will be good for 16 amp, but what about the internal wiring? from the connection onwards? Will this wiring be able to cope with 16 amps?... The cable fitted may well be what the installer happened to have with him. Don't forget that there will be wiring inside the boiler that is not protected by the fuse on the PCB and so relies on protection from the fuse in the fused spur..

now thats probably the right answer.

I cant even begin to tell you both how wrong you are!

lets get this straight before we go any further. the spur , protects the cable feeding the boiler...not the boiler...

All I will say is, read the 17th edition, and or any basic electrical principles textbooks.
I could quiet safely have wired in a 35mm2 cable feeding that boiler fused much higher than 13A! (Don’t have my current tables handy to quote a fuse size), 185mm2, even!!
You might want to read up on discrimination with downstream circuit protective devices...as what that BG engineer did was wrong, and I have since rectified this!
Ye im not a gas engineer, but I am an electrical engineer, BEng hons, electronic engineering. Member if IET.

I dont give a s**t if your a rocket scientists, MI's state 3 amp then its 3 amp, you do something else and something goes wrong to do with it its your a**e boy

there is 3A CPD protecting the boiler, supplied byIDEAL!! like i said...electrical principles...

please dont wire anyones house!

 

[OLLIE20]

Sorry dne get abreviation CPD, explain, but it doesnt matter bout your principles and so on, what manufacturer says goes, not what you work out is best, trust me

 

[gdallas]

Sorry dne get abreviation CPD, explain, but it doesnt matter bout your principles and so on, what manufacturer says goes, not what you work out is best, trust me

CPD = Circuit protective deivce

ye im not trying ot be an arse!! honest... iim just trying to let explain how things are!

the boiler is protected by a 3A fuse (supplied by ideal), i.e. the incoming supply to the boiler.

the BG engineer changed the upstream fuse (the spur) from 13A to 3A when he serviced myt boiler. thatt meant there was 2 3A fuses in series. the spur, and the the one in the boiler. this is wrong on so many levels.

Like i said, not trying to winf you up. i just think you missundersdtand me



if yo like i can do an Amtech calculation tomorrow at work to show you any size of cable, with appropriiate fise size would work; provding the ites less than the breakers at the consumer unit, AND the characteristics discriminate ok!

 

[OLLIE20]

The fuse in the fuse spur should be 3 amp not 13, and the on PCB is usually smaller than 3 amp. Ideal will tell you to fit 3 amp fuse to external fuse spur,i dont understand what you think is wrong, if a manufacturer states something tats how it is to be dne, in my opinion BG engineer was spot on

 

[OLLIE20]

Sorry dne get abreviation CPD, explain, but it doesnt matter bout your principles and so on, what manufacturer says goes, not what you work out is best, trust me

CPD = Circuit protective deivce

ye im not trying ot be an a**e!! honest... iim just trying to let explain how things are!

the boiler is protected by a 3A fuse (supplied by ideal), i.e. the incoming supply to the boiler.

the BG engineer changed the upstream fuse (the spur) from 13A to 3A when he serviced myt boiler. thatt meant there was 2 3A fuses in series. the spur, and the the one in the boiler. this is wrong on so many levels.

Like i said, not trying to winf you up. i just think you missundersdtand me



if yo like i can do an Amtech calculation tomorrow at work to show you any size of cable, with appropriiate fise size would work; provding the ites less than the breakers at the consumer unit, AND the characteristics discriminate ok!

If you like i can send you Caradon Ideals literature on the matter, which will stand up and take presedent of any electrical calculation you want to put to me. If something went wrong down to fuse and you were in court on the stand and you did your way instead of the MI's way, that would be you, nite nite, clear a bed in strangeways

 

[gdallas]

The fuse in the fuse spur should be 3 amp not 13, and the on PCB is usually smaller than 3 amp. Ideal will tell you to fit 3 amp fuse to external fuse spur,i dont understand what you think is wrong, if a manufacturer states something tats how it is to be dne, in my opinion BG engineer was spot on

dude, the fuse in the spur doesnt need to be 3A. the fuse ion the spur needs to be less than or equal to the rated current for the cable, as per the wiring regulations, 17th edition. if that cable feeding the boiler was rated for 40A, then I could install i 32A fuse in that spur, for example.... like i said that would be dependant on the breaker upstream, whcih would never be that large, as it would need to be a 40A breaker.... which is over kill, but not wrong, or unsafe

you obvioulsy dont understand electrical systems...lets leave it at that

 

[gdallas]

Sorry dne get abreviation CPD, explain, but it doesnt matter bout your principles and so on, what manufacturer says goes, not what you work out is best, trust me

CPD = Circuit protective deivce

ye im not trying ot be an a**e!! honest... iim just trying to let explain how things are!

the boiler is protected by a 3A fuse (supplied by ideal), i.e. the incoming supply to the boiler.

the BG engineer changed the upstream fuse (the spur) from 13A to 3A when he serviced myt boiler. thatt meant there was 2 3A fuses in series. the spur, and the the one in the boiler. this is wrong on so many levels.

Like i said, not trying to winf you up. i just think you missundersdtand me



if yo like i can do an Amtech calculation tomorrow at work to show you any size of cable, with appropriiate fise size would work; provding the ites less than the breakers at the consumer unit, AND the characteristics discriminate ok!

If you like i can send you Caradon Ideals literature on the matter, which will stand up and take presedent of any electrical calculation you want to put to me. If something went wrong down to fuse and you were in court on the stand and you did your way instead of the MI's way, that would be you, nite nite, clear a bed in strangeways

FAIL!!! The Electricity at Work Regulations 1989 > MI. understand what your talking about, boy...Good night!!