Will a fuse box to consumer unit upgrade fix the issue?

[JohnW2]

I havent tried switching the mcbs off. Without them on theres no power to the circuit thst buzzes under a high load

Ah - you beat me to it and answered my next question! What is the 'rating' (maybe 30A?) of the plug-in MCB on the circuit which buzzes? What are ratings of the other plug-in MCBs?

Kind Regards, John

 

[musicman1987]

Theres 2 in the board- 1 5amp for the light ring and 1-20 which is the circuit that I believe buzzes. But it does only do it when multiple big appliances are running. Given that its only 20amp, could this buzzing be the line reaching its maximum beforenit would trip?

to be honest, if the lesson from this is keep the load low I don't mind. As long as its safe. But either way, I still will have this box upgraded. Apartnfrom anyhing else, id rather have some rcd protection for my little bundle of joy thats coming

 

[RF Lighting]

Bet you replacing that breaker will cure the fault. Even a first year apprentice out to be able to diagnose a fault like this.

Save the money you were going to spend on the new cu and put it into the saving account to get your rewire done.

 

[JohnW2]

Theres 2 in the board- 1 5amp for the light ring and 1-20 which is the circuit that I believe buzzes. But it does only do it when multiple big appliances are running. Given that its only 20amp, could this buzzing be the line reaching its maximum beforenit would trip

Ah - that could well be the explanation. You previously wrote:

It only happens if there are 2 high pull devices running in the circuit (such as the dishwasher and washing machine). If only 1 is running, there's no buzz.

If the 'high pull devices' are each 'pulling' about 13A, then one of them on a 20A MCB would be fine, but two at once (26A) would be significantly 'OTT' and therefore could well result in the MCB buzzing.

If you want to be able to run two such loads simultaneously, you'd really have to have at least some rewiring done, so that you had a 30A or 32A circuit.

Kind Regards, John

 

[musicman1987]

Really? As simple as that?

 

[musicman1987]

So as long as its managed, it should be okay until I can get it upgraded to a 30amp circuit?

Am I right in thinking its only when its buzzing that an issue could occur under the current set up?

 

[JohnW2]

Really? As simple as that?

Quite possibly - if you were designed to have a maximum of 20A passing through you and someone pushed 26A through, don't you think that you might 'buzz' a bit?

Kind Regards, John

 

[JohnW2]

So as long as its managed, it should be okay until I can get it upgraded to a 30amp circuit?

If by 'managed' you mean not trying to run two 'high pull' (~13A) loads at once then, yes, if that is the explanation for the buzzing, then it should be OK

Am I right in thinking its only when its buzzing that an issue could occur under the current set up?

Probably - although that obviously depends on whether or not the 'explanation' I have suggested is correct!

Kind Regards, John

 

[musicman1987]

To be honest, that is what I thought it could be. But being the csrefuk type I thought I'd ask an electrician to check it out. I just wish he would have told the wife that. It would make sense to me that if you push something to its limit, its bound to do something out of the ordinary. Should it not trip before it gets too much? I mean, I have touched it after its buzzed and it hasnt been hot to touch...

A new CU isn't going to fix that then, is it? The wiring is still gonna need attention across the circuit, because it all seems to be on one loop for upstairs and down.

 

[RF Lighting]

A new cu may or may not buzz, but it certainly won't cure the problem.

 

[flameport]

A new CU on it's own won't change anything.

A 20A circuit is a fairly unusual thing to be found in an older property, which suggests either whoever fitted that MCB chose the wrong one, the wiring has been altered in various undesirable ways, or both of those things.

The presence of mixed fuses and plug in breakers often indicates that one or more of the fuses was failing regularly, and someone shoved in the MCB to make it easier to reset, rather than fixing the problem(s) that were causing fuses to fail.

 

[musicman1987]

But it would be safer? I want to do the best for the system- of course I do. But I really dont have the 000s needed to rewire right now. If a CU is going to make the system safer then I will get this done now and a rewire in the near future. Or is it even worth that step when its a matter of not over loading the 20amp circuit?

 

[RF Lighting]

If you can maybe save up and get the rewire done in a couple of years then there's no point having the fusebox replaced now.

Whist new CUs are slightly safer, as they will incorporate RCD protection too, there was a time when all we had was rewireable fuse boxes and they were perfectly fine and still are.

 

[JohnW2]

To be honest, that is what I thought it could be. But being the csrefuk type I thought I'd ask an electrician to check it out. I just wish he would have told the wife that. It would make sense to me that if you push something to its limit, its bound to do something out of the ordinary. Should it not trip before it gets too much?

A 20A MCB will allow 26A to pass for a long time before tripping - even 29A may take up to an hour to trip - but those currents are more than enough to upset the MCB, maybe reduuce it's life, and quite possibly cause it to buzz.

A new CU isn't going to fix that then, is it? The wiring is still gonna need attention across the circuit, because it all seems to be on one loop for upstairs and down.

You're probably right. If that 20A MCB is appropriate for the circuit, then changing the CU (necessarily still having a 20A MCB for that circuit) will not alter the situation. However, as has been suggested, it's just possible that the circuit itself (wiring) is capable of more than 20A, in which case it might possibly be that a larger MCB could be used, thereby alleviating the problem. However, only an electrician who has investigated the installation would be able to tell you if that is the case.

Kind Regards, John

 

[john4703]

So I did what I thought was best and called an electrician. He came out and after checking over the fusebox and telling me that no one has had a proper look at it in years (we've only been here a couple),

If you have only been in the house a couple of years do you still have the reports on the condition of the electrics from when it was surveyed. They may tell you nothing but equally may be full of information.