I thought my mains was sorted !

Posted by: Ade Archer on 26 November 2001

Last year I had a seperate spur installed by an electrician, to whom I had explained that it was recommended by Naim that I get one rated at least 30amps. The spur was installed and I thought nothing more of it really. I had looked at the individual breakers in the past, but hadn't noticed the rating. Today, in Homebase, I looked at the breakers more closely, and noticed that the had figures 'B 16','B 30','B 40' on them, the figure after the 'B' corresponding to the amp rating. On my return home, I had a look at mine to check, and found that my HiFi spur had a 16 amp breaker. I thought this would explain why I sometimes have trouble switching on my Hicap and 250 without it tripping, so I went and got a 40 amp breaker to replace it.

The difference is huge ! Many of the criticisms I would have of the sound of my system have been resolved, and this is without the XPS I had borrowed recently.
Is it the case that the 16 amp breaker was some kind of bottleneck, as even though it is recommended to install at least a 30 amp spur, I am surprised by the difference, since all the equipment plugs have 13 amp fuses.

Cheers
Ade

Posted on: 26 November 2001 by Matthew T

You should put in a 30amp breaker not 40. If the cable is rated at 30amps then you could just cook your cable and have a burnt down house. Should to advisely affect the sound.

cheers

Matthew

Posted on: 26 November 2001 by Ade Archer

Thanks Matthew,
Has anyone experienced any benefits in going from a 30 amp spur to a 45 amp one. I would be able to replace the cable myself if it's worthwhile doing.
Also, can anyone explain why I've seen these benefits of uprating the circuit breaker.

Cheers
Ade

Posted on: 26 November 2001 by Mick P

Ade

Fit a 30 amp fuse without delay.

If your cable burns out and causes a fire, due to the 40 amp fuse being fitted...your insurance is null and void.

Regards

Mick

Posted on: 26 November 2001 by Ade Archer

The breaker is switched off and the system is plugged into another socket now to keep it warm until I can see what I'm doing tomorrow (I've got to turn off the whole house supply to work on the board.) But I am still interested to know if a better long term solution is to run what I think would need to be 10mm cable to the system, as this would be a relatively straightforward operation.

Cheers
Ade

Posted on: 26 November 2001 by Martin Payne

I have been told that 16sq.mm cable is not that much harder to work with than 10sq.mm, and would probably fit into the same sockets.

I'm not sure whether to believe this, but I bet it's a right B******D to fit. I use 10sq.mm, but this is on a 5m run.

I might consider going to the next grade if very long runs were required.

BTW, go to an electrical wholesaler instead of your local DIY store. Stuff is much cheaper, and they will be able to advise what will work together.

You may get a bit (or a lot) of stick for over-specifying, but they will be able to tell you what might be dangerous, if they have a few minutes to discuss what you're trying to do.

I probably wouldn't use a breaker rated above 45A, even if your cable is rated above this. That's a frightening amount of power if anything ever goes wrong!

cheers, Martin

Posted on: 26 November 2001 by Mike Harris

quote:
my HiFi spur had a 16 amp breaker. I thought this would explain why I sometimes have trouble switching on my Hicap and 250 without it tripping, so I went and got a 40 amp breaker to replace it.

Somethings wrong...

Posted on: 26 November 2001 by Ade Archer

Mike,
Are you suggesting there's something wrong with my equipment, because I'm confident there isn't. I'm not the only person here that has had this problem. I have no problems whatsoever with the equipment other than the breaker tripping occasionaly when trying to switch on my Hicap and 250 (I can usually get one of them on but it sometimes trips as soon as I switch the other one on). It is obviously the sudden load that these two create that upsets the circuit breaker, and it has never tripped once whilst everything is powered up.

Cheers
Ade

Posted on: 26 November 2001 by Mike Hanson

How much time do you wait between powering up each component? Whenever I switch my stuff on after being off (and it's OFF as little as possible), I do it from the top down. First the XPS, then the Super-Cap, then 135 #1, followed by 135 #2. I usually wait about five seconds between each component.

I think it's important to do it top down, so that each component being powered up sees something "normal" being fed into its inputs. It almost sounds like you turn on the 250 first, followed quickly by the Hi-Cap.

Perhaps the Hi-Cap sends a surge to the pre-amp, which is fed back into the power amp. You get the Hi-Cap saying "charge my caps", while the 250 is charging its own caps and simultaneously trying to deal with the surging signal from the pre-amp. The whole system asks for too much power, and your breaker trips. (At least that's my ill-educated theory. )

-=> Mike Hanson <=-

Posted on: 27 November 2001 by Ade Archer

Mike H:

quote:
It almost sounds like you turn on the 250 first, followed quickly by the Hi-Cap.

Mike, I turn the Hicap on first as that way the speakers don't get any spike since the 250 is off. I wait a few seconds to turn on the Hicap, but it still occasionaly trips.
As Jason has found, I am assuming I won't have any problems when the circuit breaker is uprated.

Cheers
Ade