Tripping circuit breakers?

[Gazzip]

Yesterday I traded in my Bryston 7BSST2's and upgraded to a second hand pair of Bryston 28BSST2's. I got them home, plugged them in, and the music flowed. Lovely!

With it being Valentine's eve yesterday I only had an hour or so with them before I went out for dinner with the other love in my life. As this is new electrical equipment (in my house anyway) for safety's sake I turned the amps off before we left the house.

This morning I popped back upstairs to turn them back on. Clunk! The circuit breaker on the amp had tripped, along with the mains circuit breaker for the dedicated spur to my power amps. I reset both and tried again only for the same thing to happen. I tried the other amp which fired up fine once or twice but which is now doing the same as the other amp and is tripping itself/the mains. To summarise I cannot turn my amps on without them both tripping themselves and the mains.

Any ideas anybody? The spur to the amps is dedicated only to them, the hard wired cables are 2.5mm Supra LoRad, and the circuit breaker is a 20A Type B.

Could this be the initial hard startup current draw tripping my circuit, or is it more likely a fault with the amps? Thanks. G

 

[Vladimir]

Each monoblock is rated at 1465W power consumption at its continuous 1000W of output at 8 ohms. 13A * 230V = 2990VA is the best your mains can do. Your monoblock at power up may suck full 2930W, or in that monstrous vicinity, to charge the battalion of caps. The first 60Hz cycle of the large torroid may suck over 100A. This is why Bryston has installed resetable circuit breaker (imagine unscrewing both amps and changing glass fuses each time they flop).

You need inrush current limiter installed in your fuse box for the amplifier line. The amp is fine. It just has a VERY healthy appetite.

 

[Gazzip]

Each monoblock is rated at 1465W power consumption at its continuous 1000W of output at 8 ohms. 13A * 230V = 2990VA is the best your mains can do. Your monoblock at power up may suck full 2930W, or in that monstrous vicinity, to charge the battalion of caps. The first 60Hz cycle of the large torroid may suck over 100A. This is why Bryston has installed resetable circuit breaker (imagine unscrewing both amps and changing glass fuses each time they flop).

You need inrush current limiter installed in your fuse box for the amplifier line. The amp is fine. It just has a VERY healthy appetite.

Really? It is a UK product that is certified for use in a domestic environment, which would suggest it is plug and play?

 

[Vladimir]

Really? It is a UK product that is certified for use in a domestic environment, which would suggest it is plug and play?

It is. As long as you plug it in through an inrush current limiter. *biggrin*

TEB-325 mounting switch-on current limiter
Description[/b]

For devices with high starting current. Prevents fuse elements from being triggered. Ideal as ballasts for transformers and primary power supplies.

 

[toyota man]

Hi how far is the amp from your trip board ? is it tripping a 20A type B trip or is it tripping an RCD or a RCCB

 

[Gazzip]

Hi Toyota Man,

lt is about 6m from the Consumer unit and it is tripping a 20A type B. The amp has its own inbuilt trip switch protection which is also tripping. What is weird is that:

1) it worked the night before on that circuit

2) the second amp is now doing it

Any ideas? I have a lot of time for Vladamir as I think he has a very good understanding of electronics in general, but I can't accept (maybe wrongly) that I need to up spec my domestic power supply to accommodate a domestic amp. Possibly a more "manly" type C breaker yes, but one of thingamajig wotsits seems a little extreme, no?

 

[abacus]

A type C breaker may help as it is more surge resistant, (MCBs are notorious for tripping with switch on surges) if not then you may need to to get an MCB designed for DOL motor control (See your local electrical retailer) to solve the problem.

Domestic sockets are normally on a ring main with a 32A breaker which gives a much greater headroom than a 20A breaker, and the amplifier manufacture probably assumes that this is what they will be connected to.

Hope this helps

Bill

 

[Gazzip]

Thanks Bill. I am having the Type B MCB replaced with a Type C tomorrow so we shall see.

Although here is weirdest thing: I popped up to my man cave about 45 minutes ago just to look at my Hifi rendered silent (sad I know), and I thought what the heck one more try can't hurt while I am up here. I reset the left channel amp's inbuilt trip, pushed the power button, and hey presto! We have lift off! Same process with the other monoblock and I have had uninterrupted music ever since.

As both amps "failed" almost simultaneously and both have recovered at the same time I think we can safely say that it is a problem with my electrics confusing the startup procedure of the amps and not with the Bryston electronics. I think I will still have the Type C MCB fitted tomorrow and also get the electrician check everything over, check the incoming supply for fluctuations etc. I hate mysteries, especially those associated with mains electricity, my home, and many, many £K of Hifi equipment.

 

[Vladimir]

Adding higher rated breakers exposes the gear to higher risk from main surgers but it is cheaper than inrush current limiters.

 

[Gazzip]

Adding higher rated breakers exposes the gear to higher risk from main surgers but it is cheaper than inrush current limiters.

Hi Vladimir. I have been doing some research in to my amps today and it turns out that Bryston power amps have ICL's built in to their soft start mechanism. There is a few second delay after pressing the on button before the amp kicks in to operational mode. Is this going to do the same thing as you suggest?

 

[Vladimir]

Hi Vladimir. I have been doing some research in to my amps today and it turns out that Bryston power amps have ICL's built in to their soft start mechanism. There is a few second delay after pressing the on button before the amp kicks in to operational mode. Is this going to do the same thing as you suggest?

That may only serve as a safety mechanism for the amp circuit, but it will still suck huge power from the mains on startup, making your main house circuit breakers trip.

If you're having an electrician coming in, best to have him check everything and he will know what to do. If you are changing the breakers to higher rating, try to get away with as little as possible. If 25A works, don't go to 35A or 50A. Having a too high rated fuse is effectively having no fuse and no protection form mains surges.

 

[Gazzip]

Phew! It is shorts weather in my listening room. Three hours of low level listening and my room has gone from a moderate 22C up to a balmy 26C. These big Brystons run hotter than the sun! Apparently they are pure class A for the first few percent, but in a 1200W amp into 4 ohms that is pretty much class A all of the time at reasonable listening levels!

 

[andyjm]

Hi Vladimir. I have been doing some research in to my amps today and it turns out that Bryston power amps have ICL's built in to their soft start mechanism. There is a few second delay after pressing the on button before the amp kicks in to operational mode. Is this going to do the same thing as you suggest?

That may only serve as a safety mechanism for the amp circuit, but it will still suck huge power from the mains on startup, making your main house circuit breakers trip.

If you're having an electrician coming in, best to have him check everything and he will know what to do. If you are changing the breakers to higher rating, try to get away with as little as possible. If 25A works, don't go to 35A or 50A. Having a too high rated fuse is effectively having no fuse and no protection form mains surges.

Bryston make a big deal about the 'phase' control of their system that allows the storage caps to slowly charge on switch on, so inrush current really shouldn't be a problem. Something somewhere must be adrift if the breakers are tripping.

Just as a FWIW, the circuit breaker rating is chosen to protect the cabling downstream of the breaker. Generally, in the UK a 2.5mmsq spur is rated at 20A, a 2.5mmsq ring main rated at 32A. It is possible to change the trip dynamics of the breaker (to a type C for example) so that the breaker is more resistant to startup surges in (say) motor starting circuits - but this requires a sparky to review the cabling and installation, it isn't just a simple swap. Breaker current ratings should not be increased over the ratings above.

We don't usually get mains surges in the UK, the mains is pretty clean.

The advice to run a separate spur to the consumer unit comes from the US where 110V is pretty gutless and wiring generally not installed in a ring. In the UK, the 'best' way to power a high current device would be from a standard ring, not a spur.

 

[toyota man]

Hi Gazzip if you are worried about overload protection ( fault current) you could have a 16A type C trip fitted this would probably carry your load and trip out quickly should a fault develope .

 

[toyota man]

Hi Gazzip how did it go ?

 

[Gazzip]

Hi Gazzip how did it go ?

C Type MCB fitted to the same amps rating as the B Type that was removed and all seems to be working well.

Eyebrows were raised when I initially tripped the circuit by turning an amp on to demonstrate the issue. He slowly removed his amp meter sensors from the circuit breaker connections, turned to look me in the eye and said; "what in the hell have you got in there?!". Apparently it sucks the circuit dry of current on switch on.

There goes my EPC C Rating.....