63A main panel fuse blows if power outage occurs

Irish Steve

As the title says, just had a call from my daughter, they've had issues at their house in Duleek with the main 63A fuse in the panel blowing when the power comes back on after an area failure, and then today, ESB were doing a significant upgrade in their area, so they were off for most of the day, and then when it did come back on, they had 3 fuses blow before the power stayed on.

There's nothing fancy like Solar or EV charging on the system, it's a basic 4 bed semi, and there's no out of the ordinary loads attached to the system.

There's nothing unusual about the house or the wiring that I'm aware of, and there's not any issues with any breakers or other trips dropping out at any time, but this issue has been happening for a while, we have heard a suggestion that it's related somehow to the upgrade to a smart meter that happened a while back, but I'm not convinced, if there was an issue of this nature, I'd have expected it to have shown up in places like this, but I've not seen any similar reports.

So, first, has anyone had any experience of a fault of this nature, and second, where to start in trying to find someone with some above average diagnostic skills to work out what's going on?

2011

I imagine that the issue is external to the installation and most likely related to the outage in the first place, a transient voltage spike most likely.

Irish Steve

https://www.boards.ie/discussion/comment/121777391#Comment_121777391

I have to admit, a one off would indeed seem to back that up, but tonight, the outage was a scheduled maintenance update, there's a new housing estate being built across the road from their estate, and there was a 11Kv overhead passing over a line of new houses, so they've been removing the overhead and replacing it with underground cables for a span of about 200 metres, so not a fault as such, just no way to switch their estate to an alternate incoming feed for the duration of the work, but when it came back on, it took 2 main fuses out in quick succession before it stayed on, I got them a box of 10 after the last time this happened, as they didn't have any spares there, my daughter was on her way home at the time so doesn't know if it was a case of instant blow, or a few seconds after it came back on, but she's obviously concerned that there's something untoward going on

Now it's stayed back on, it will most likely stay that way until the next time they get a cut that affects their area, would the distance from a sub station have any influence on this, there's a (probably) 11Kv to low voltage cabinet not far from the house, they're on an estate, so if it was a weird external issue, I'd have expected a number of houses to be affected by something like this.

Bruthal.

If power comes back, fuse blows, and then subsequent fuses blow with no power outage from the supply, it seems to suggest something in the installation. Like its happening when power is off to the house for a while before being switched on again. One cause can be several inductive loads trying to start at power up. I seen it in shops with mcbs tripping where a load of fridges come on together after power off for a time, where as normally they would never be all starting at precisely the same time except when power off for a while. Had to switch each fridge off and then back on one at a time. Probably not the cause here though.

Maybe try switching all breakers off before attempts at replacing main fuse, then breakers back on one at a time And see what happens.

Irish Steve

https://www.boards.ie/discussion/comment/121777578#Comment_121777578

That's worth a try, and it could be a way forward, there's not a lot of surge loads as such in the house, a fridge and a freezer would be the only definite loads when the power comes back on, apart from that, the remaining loads would all be low value, TV's, chargers, computers, stuff like that, so I will suggest that route for the future, and see if it makes any difference, this is the first time where it's taken out more than one fuse, previous times, it's stayed on when the blown fuse is replaced.

Bruthal.

Inductive loads would be unusual to take out main fuse and not mcbs anyway. But I'd definitely try the mcbs all off next time anyway.

Irish Steve

https://www.boards.ie/discussion/comment/121777674#Comment_121777674

That will be the plan, and I'm going to see who it was that said about the smart meter, in that I'm not sure if it wasn't an ESB emergency response unit that said it, if that's the case, I don't know how we set about finding out more.

10-10-20

Do they get unusual dimming of lights during normal use at all? Kinda wondering if they have a localised voltage issue is it causing the amps to shoot up... or something odd like that.

Irish Steve

Not sure, and I will ask, that's a valid thought, a long time ago now, we were on the wrong transformer here, and a heavy load dropped our supply to somewhere around 180 Volts, they put a chart recorder in, and we were able to get it to record as such, they had to move a whole block of 15 houses on to a different transformer, and that solved the problems for us, we were the end of that particuar line, I hadn't actually thought of voltage drop issues, Thanks for that.

meercat

Are you 100% sure they are 63amp fuses.

can you post a photo of them

obviously turning everything on together may overload a lower rated fuse

replacing the main fuse with an 63a mcb may help but not resolve this issue

kirving

https://www.boards.ie/discussion/comment/121777578#Comment_121777578

I had similar in an apartment recently too. We had a pump to maintain water pressure, washing machine, dryer and fridge. Occasionally the main breaker would trip, and all I could put it down to was the pump cycling at the same time as one or two of the others were also starting up and causing a current spike.

We also had around 600W of 12V LED lighting which was on a transformer, but would that cause a constant inductive load?

Irish Steve

https://www.boards.ie/discussion/comment/121777838#Comment_121777838

Yes, absolutely sure they are 63A fuses, D02 (Neozed) 63A on both the box and printed on the fuses,

neozed.jpg

THe only concern about using a 63A MCB would be that if the MCB is slower tripping than a fuse blowing, there's a chance of blowing the ESB sealed 63A fuse in the meter cabinet, and if that goes, it's not just a case of throwing a new fuse in, and there's a special needs child in the house who doesn't cope well without things like her tablet, and the internet, so getting the power back quickly is a priority if at all possible, she was here with us all day today because of the scheduled outage.

10-10-20

I think its all the capacitive loads these days, chargers, power supplies, dehumidifiers; anything with stand-by power; all with high inrush currents due to the X and Y capacitors and pF correction.

Many of my MCB's drop on the reapplication of power, but in fairness I have a fair few IT devices connected.

meercat

Have you an isolator in the meter box so a rec can replicate this issue and do some testing whilst being energised

not a big fan of neoz fuses and holders so I’d recommend replacing it anyway

its unlikely (but not impossible)the Esb main fuse would ever blow with a surge . Its high rupturing capacity.

Fine Day

Intermittent faults like this can be tricky to get to the roote of. How long are they in the house and has it always done this or is it a recent thing.

I would switch of power at the meter and replace the main 63 amp switched fuse unit that is blowing. Also check all the other connections when there to make sure everything is tight. You have to start somewhere and this is a relatively inexpensive replacement for an electrical competent person to do.

Cuddlesworth

She should really ask her immediate neighbors if they have seen anything odd. Electronic devices failing frequently, lights flickering/dimming, things with motors making odd noises etc.

If it's not just her seeing the issue, they all need to contact esb.

tomhammer..

Check the fuse unit for damage anyhow

Bruthal.

To replicate, just switching off at the main switch in DB should do the same thing. But would need to be left off for a length of time like and hour or similar probably.

tomhammer..

https://www.boards.ie/discussion/comment/121779781#Comment_121779781

Seems highly unusual to me anyhow

Main fuse blowing on power restoration

Irish Steve

https://www.boards.ie/discussion/comment/121778807#Comment_121778807

No isolator they were not a requirement when the house was built, it's about 20 years old, so the Neozed switch fuse is the isolator, so we can't do anything significant test wise. I think I'm going to work on some of the thoughts here, and see if there's any pattern locally, immediate neighbours won't be any help, with how the estate is laid out, and the location of the local transformer, I think they're fairly close to the end of the line, which might give some credibility to the thought of low voltage being a factor, in that everybody will be surging in the same way on a resoration. What is for sure is that this is unusual, so we will have to see if there'a any other significant factors at play.

Bruthal.

https://www.boards.ie/discussion/comment/121779891#Comment_121779891

Unusual alright. As I was saying, the nearest I seen to it was in shops with groups of fridges. Circuits wouldn't reset after power cuts because all compressors would try to start at same instant, which would never happen unless they all left off for a while. Had to plug out and all back in one at a time. Seems unlikely in a house though.

tomhammer..

Usually if there's an outage or thunderstorm i switch off circuits at main board, RCDs etc.

Switch back on when storm is over or power reliably restored

Lenar3556

I think it’s more likely the issue lies within the installation rather than on the supply side.

The 63A fuse would take very considerable overcurrent to cause it to blow that quickly. And there is no question really but that this current is being drawn at some point downstream from the fuse and within the house. It’s conceivable that this is being driven by a higher voltage coming into the house at a particular time, but it really would need to be rather extreme - and there is no MCB tripping?

It doesn’t quite add up, but something is wrong and it needs to be identified to ensure there isn’t a fire hazard.

MrMusician18

https://www.boards.ie/discussion/comment/121783722#Comment_121783722

Would it not be a low voltage that causes the current to spike? Could it be that because all the neighbours are drawing down as well when power is restored that causes the voltage to be suppressed, resulting in a higher draw current on the OPs property?

I think it's likely that a few devices, pumps or motors are drawing big inrush or starter currents on restoration and the sum of all these are resulting in the blown main fuse.

If a transient low voltage is the ultimate cause then is there a fix? Possibly only waiting until supply voltage has stabilised and then restoring power to the circuits one by one?

tomhammer..

There's low voltage release relays, phase failure relays etc that cut power when voltage drops or phase is lost . They'd be commonly used in industry

Other than that imo it's prudent to switch off circuits during these times of outage storms etc

Lenar3556

https://www.boards.ie/discussion/comment/121783800#Comment_121783800

I don’t see how low voltage supplied to 230V loads in a domestic house could lead to a such a significant overcurrent event that is sufficient to take out a 63A fuse in such short order.

Inrush could be a factor, but I still don’t think it comes even close to explaining what is required to blow the 63A fuse in what we understand to an average 20 year old build? Presumably without a heat pump.

Difficult to see where is the potential for this 80-100A+ current to flow? And why is it not tripping any MCB’s which would typically be of more sensitive tripping characteristics than the 63A neozed and most of which would also be half the design tripping current?

tomhammer..

It seems a very odd problem. The fuse unit should be inspected as a precaution anyhow

Assuming power is being restored properly after the outage it's the equivalent of a main fuse blowing after turning off the main switch fuse for a period of time

Not something i've ever noticed happening

Bruthal.

https://www.boards.ie/discussion/comment/121783800#Comment_121783800

Motor starting currents are higher, the higher the voltage.

Antenna

Any chance that any SPDs (Surge Protection Devices) had been added to the installation?

Could these go bad in such a manner to sometimes conduct when they shouldn't, shorting out the supply?

tomhammer..

https://www.boards.ie/discussion/comment/121786415#Comment_121786415

There's indicators on them anyway green /red afaik worth checking if fitted

Haven't fitted any domestic ones but afaik they mostly have 32amp MCB protection

There's one below . UK board with tails in top of isolator and a 40amp MCB . I've mostly seen them shown with 32A

tomhammer..

Its worth inspecting the board anyhow see is there any unusual issue inside

Rodents or something unusual,dont think they could cause that issue