A friend of mine is a bit obsessive about catastrophe planning. He
wonders: if there is a power cut, when the power is restored could
there be a surge that could damage a fridge or freezer?

My intuition is that a compressor is sufficiently robust to cope with
fluctuations. I also read that the stopping and starting of the
compressor could damage the surge protector anyway.

(I worked in a lab one summer where there was a Chinese guy. If
anyone said 'fluctuations' he would respond 'Fluck you Europeans')

On 15/10/2022 10:59, Scott wrote:
> A friend of mine is a bit obsessive about catastrophe planning. He
> wonders: if there is a power cut, when the power is restored could
> there be a surge that could damage a fridge or freezer?
>
> My intuition is that a compressor is sufficiently robust to cope with
> fluctuations. I also read that the stopping and starting of the
> compressor could damage the surge protector anyway.
>
> (I worked in a lab one summer where there was a Chinese guy. If
> anyone said 'fluctuations' he would respond 'Fluck you Europeans')

The failure rate of domestic surge protectors possibly exceeds the
failure rate of what you are trying to protect.
--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 15/10/2022 11:15, alan_m wrote:
> On 15/10/2022 10:59, Scott wrote:
>> A friend of mine is a bit obsessive about catastrophe planning.  He
>> wonders: if there is a power cut, when the power is restored could
>> there be a surge that could damage a fridge or freezer?
>>
>> My intuition is that a compressor is sufficiently robust to cope with
>> fluctuations.  I also read that the stopping and starting of the
>> compressor could damage the surge protector anyway.
>>
>> (I worked in a lab one summer where there was a Chinese guy.  If
>> anyone said 'fluctuations' he would respond 'Fluck you Europeans')
>
>
> The failure rate of domestic surge protectors possibly exceeds the
> failure rate of what you are trying to protect.

What are the thoughts on a whole house SPD fitted in the CU?

On Saturday, 15 October 2022 at 10:59:57 UTC+1, Scott wrote:
> A friend of mine is a bit obsessive about catastrophe planning. He
> wonders: if there is a power cut, when the power is restored could
> there be a surge that could damage a fridge or freezer?

no

> My intuition is that a compressor is sufficiently robust to cope with
> fluctuations. I also read that the stopping and starting of the
> compressor could damage the surge protector anyway.

no
There is an excess of bs talked about 'surges'. In >99.9% of cases 'surge absorbers' just take people's money & give them a fire risk.

On Saturday, 15 October 2022 at 13:54:18 UTC+1, Animal wrote:
> On Saturday, 15 October 2022 at 10:59:57 UTC+1, Scott wrote:
> > A friend of mine is a bit obsessive about catastrophe planning. He
> > wonders: if there is a power cut, when the power is restored could
> > there be a surge that could damage a fridge or freezer?
> no
> > My intuition is that a compressor is sufficiently robust to cope with
> > fluctuations. I also read that the stopping and starting of the
> > compressor could damage the surge protector anyway.
> no
> There is an excess of bs talked about 'surges'. In >99.9% of cases 'surge absorbers' just take people's money & give them a fire risk.

+1

I make a point of actively avoiding them in extension leads.

There could be some benefit in having a whole house type if you have long
overhead power lines which are prone to induced voltage spikes from
lightning. However, if there is a nearby lightning strike nothing will protect
you.

The power supplies in most electronic equipment will tolerate significant
spikes and surges for short periods. There will typically be a 400Vdc
capacitor after the bridge rectifier in a switching power supply. This will
usually tolerate 20% overload for short periods. At 250V ac mains input the
capacitor will be charged to about 350V dc, but it will generally be able to
tolerate over 500V for short periods.

John

On 10/15/2022 5:59 AM, Scott wrote:
> A friend of mine is a bit obsessive about catastrophe planning. He
> wonders: if there is a power cut, when the power is restored could
> there be a surge that could damage a fridge or freezer?
>
> My intuition is that a compressor is sufficiently robust to cope with
> fluctuations. I also read that the stopping and starting of the
> compressor could damage the surge protector anyway.
>
> (I worked in a lab one summer where there was a Chinese guy. If
> anyone said 'fluctuations' he would respond 'Fluck you Europeans')
>

The old refrigerators were very robust.

They could regularly last forty years.
Without a bit of preventive maintenance.

Never needed to be unplugged during a lightning storm.

It's the newer refrigerators, they don't have
the track record, to be drawing any conclusions.

A modern refrigerator, even a cheap one, can
have a CPU and low voltage DC inside. Whereas
the old refrigerators followed the "hunk of iron" paradigm.
(Timer motor and the odd relay, for sequencing.)

One of the Korean brands of modern fridge, for pentane/butane
it uses a variable speed compressor. It's hard to say
what the consequences for reliability might be, on one
of those. Compressor could be DC powered. Might not be
a scroll compressor, but perhaps a piston compressor and
a brushless DC motor. The power side exposed to mains,
would not be the same as the old refrigerators.

Since the new refrigerators tend to have metal
covers so you can't see anything, you can't even
roll the mother out and poke around. And you never
know how that stupid cover, is tied to the refrigerant
piping (thermal tape???).

Paul

On 15/10/2022 12:17, SteveW wrote:
> On 15/10/2022 11:15, alan_m wrote:
>> On 15/10/2022 10:59, Scott wrote:
>>> A friend of mine is a bit obsessive about catastrophe planning.  He
>>> wonders: if there is a power cut, when the power is restored could
>>> there be a surge that could damage a fridge or freezer?
>>>
>>> My intuition is that a compressor is sufficiently robust to cope with
>>> fluctuations.  I also read that the stopping and starting of the
>>> compressor could damage the surge protector anyway.
>>>
>>> (I worked in a lab one summer where there was a Chinese guy.  If
>>> anyone said 'fluctuations' he would respond 'Fluck you Europeans')
>>
>>
>> The failure rate of domestic surge protectors possibly exceeds the
>> failure rate of what you are trying to protect.
>
> What are the thoughts on a whole house SPD fitted in the CU?

We now fit them on a CU swap/new build/rewire as standard.

Options are available to downgrade.

On 15/10/2022 10:59, Scott wrote:
> A friend of mine is a bit obsessive about catastrophe planning. He
> wonders: if there is a power cut, when the power is restored could
> there be a surge that could damage a fridge or freezer?

Anything is possible but since fridges and freezers are inductive loads
there is more chance of the protection failing catastrophically.

Filament bulbs tend to react very badly to intermittent restarts of
mains with a few over voltage spikes thrown in. It bounces off inductors
although it might blow surge protection devices and filter capacitors.

--
Regards,
Martin Brown

On 15/10/2022 12:17, SteveW wrote:
> On 15/10/2022 11:15, alan_m wrote:
>> On 15/10/2022 10:59, Scott wrote:
>>> A friend of mine is a bit obsessive about catastrophe planning.  He
>>> wonders: if there is a power cut, when the power is restored could
>>> there be a surge that could damage a fridge or freezer?
>>>
>>> My intuition is that a compressor is sufficiently robust to cope with
>>> fluctuations.  I also read that the stopping and starting of the
>>> compressor could damage the surge protector anyway.
>>>
>>> (I worked in a lab one summer where there was a Chinese guy.  If
>>> anyone said 'fluctuations' he would respond 'Fluck you Europeans')
>>
>>
>> The failure rate of domestic surge protectors possibly exceeds the
>> failure rate of what you are trying to protect.
>
> What are the thoughts on a whole house SPD fitted in the CU?

I give you Russ Andrew.
If you are that mission critical use a whole-house UPS.

--
“The ultimate result of shielding men from the effects of folly is to
fill the world with fools.”

Herbert Spencer

On 16/10/2022 08:18, ARW wrote:
> On 15/10/2022 12:17, SteveW wrote:
>> On 15/10/2022 11:15, alan_m wrote:
>>> On 15/10/2022 10:59, Scott wrote:
>>>> A friend of mine is a bit obsessive about catastrophe planning.  He
>>>> wonders: if there is a power cut, when the power is restored could
>>>> there be a surge that could damage a fridge or freezer?
>>>>
>>>> My intuition is that a compressor is sufficiently robust to cope with
>>>> fluctuations.  I also read that the stopping and starting of the
>>>> compressor could damage the surge protector anyway.
>>>>
>>>> (I worked in a lab one summer where there was a Chinese guy.  If
>>>> anyone said 'fluctuations' he would respond 'Fluck you Europeans')
>>>
>>>
>>> The failure rate of domestic surge protectors possibly exceeds the
>>> failure rate of what you are trying to protect.
>>
>> What are the thoughts on a whole house SPD fitted in the CU?
>
> We now fit them on a CU swap/new build/rewire as standard.
Your counterpart that rewired our house also fitted one, it was
optional, but I opted for it

On 16/10/2022 08:18, ARW wrote:
> On 15/10/2022 12:17, SteveW wrote:
>> On 15/10/2022 11:15, alan_m wrote:
>>> On 15/10/2022 10:59, Scott wrote:
>>>> A friend of mine is a bit obsessive about catastrophe planning.  He
>>>> wonders: if there is a power cut, when the power is restored could
>>>> there be a surge that could damage a fridge or freezer?
>>>>
>>>> My intuition is that a compressor is sufficiently robust to cope with
>>>> fluctuations.  I also read that the stopping and starting of the
>>>> compressor could damage the surge protector anyway.
>>>>
>>>> (I worked in a lab one summer where there was a Chinese guy.  If
>>>> anyone said 'fluctuations' he would respond 'Fluck you Europeans')
>>>
>>>
>>> The failure rate of domestic surge protectors possibly exceeds the
>>> failure rate of what you are trying to protect.
>>
>> What are the thoughts on a whole house SPD fitted in the CU?
>
> We now fit them on a CU swap/new build/rewire as standard.

I've removed the RCD from our CU and replaced all the previously RCD
protected MCBs with RCBOs. Mainly because we suffered occasional
nuisance trips, due to all the electronics in this house giving quite a
high base leakage rate.

I'm gradually replacing the previously unprotected MCBs with RCBOs
(lighting, etc.). We are looking at adding an EV charger circuit soon too.

While I was at all these changes, I thought that I may add an SPD -
especially as removal of the RCD has left more spare ways in the CU and
SPDs are not too pricey.

On 16/10/2022 09:41, Martin Brown wrote:
>
> Filament bulbs tend to react very badly to intermittent restarts of
> mains with a few over voltage spikes thrown in.
As they have thermal inertia, I'm not clear how that could be ?

ARW wrote:

> SteveW wrote:
>
>> Scott wrote:
>>
>>> A friend of mine is a bit obsessive about catastrophe planning.  He
>>> wonders: if there is a power cut, when the power is restored could
>>> there be a surge that could damage a fridge or freezer

I'd expect the fridge to cope.

>> What are the thoughts on a whole house SPD fitted in the CU?
>
> We now fit them on a CU swap/new build/rewire as standard.

The MOVs in an SPD protect against over voltage, if there's any surge following
a power cut, it's likely to be high current when numerous capacitors and
compressors are all re-powered, which would be more likely to cause low voltage
.... maybe there'd be an overshoot correction of the sag?

On 16/10/2022 12:13, Mark Carver wrote:
> On 16/10/2022 09:41, Martin Brown wrote:
>>
>> Filament bulbs tend to react very badly to intermittent restarts of
>> mains with a few over voltage spikes thrown in.
> As they have thermal inertia, I'm not clear how that could be ?
>
They normally die on cold inrush current. In short being switched on

--
“But what a weak barrier is truth when it stands in the way of an
hypothesis!”

Mary Wollstonecraft

On Sunday, 16 October 2022 at 04:38:20 UTC+1, Paul wrote:
> On 10/15/2022 5:59 AM, Scott wrote:
> > A friend of mine is a bit obsessive about catastrophe planning. He
> > wonders: if there is a power cut, when the power is restored could
> > there be a surge that could damage a fridge or freezer?
> >
> > My intuition is that a compressor is sufficiently robust to cope with
> > fluctuations. I also read that the stopping and starting of the
> > compressor could damage the surge protector anyway.
> >
> > (I worked in a lab one summer where there was a Chinese guy. If
> > anyone said 'fluctuations' he would respond 'Fluck you Europeans')
> >
> The old refrigerators were very robust.
>
> They could regularly last forty years.
> Without a bit of preventive maintenance.
>
> Never needed to be unplugged during a lightning storm.
>
> It's the newer refrigerators, they don't have
> the track record, to be drawing any conclusions.
>
> A modern refrigerator, even a cheap one, can
> have a CPU and low voltage DC inside. Whereas
> the old refrigerators followed the "hunk of iron" paradigm.
> (Timer motor and the odd relay, for sequencing.)
>
> One of the Korean brands of modern fridge, for pentane/butane
> it uses a variable speed compressor. It's hard to say
> what the consequences for reliability might be, on one
> of those. Compressor could be DC powered. Might not be
> a scroll compressor, but perhaps a piston compressor and
> a brushless DC motor. The power side exposed to mains,
> would not be the same as the old refrigerators.
>
> Since the new refrigerators tend to have metal
> covers so you can't see anything, you can't even
> roll the mother out and poke around. And you never
> know how that stupid cover, is tied to the refrigerant
> piping (thermal tape???).
>
> Paul

Surge absorbers won't help them any.