power surges

[Tanya]

hi,
are power surges more likely to occur following a power outage (right
when the power is restored)?
or do they occur randomly
thank you

 

[Sam Goldwasser]

hi,
are power surges more likely to occur following a power outage (right
when the power is restored)?
or do they occur randomly
thank you

Yes and yes.

Certainly as power is restored, bad things can happen. Power may go
out again immediately if the original cause of the power outage was not
corrected. For example, if a tree branch falls across a high voltage
line, power will be cut but the automatic circuit breakers will then
attempt to restore is perhaps 30 seconds or a couple minutes later.
There may be several retries, each being hard on your electronics!

It is best if electronic equipment is totally unplugged until power is back
up and stable.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

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traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the Feedback Form in the FAQs.

 

[NSM]

| hi,
| are power surges more likely to occur following a power outage (right
| when the power is restored)?

Yes. Always a good idea to turn everything off except a light.

| or do they occur randomly

Yes, depending on where you live.

N

 

[Tanya]

Yes and yes.

Certainly as power is restored, bad things can happen. Power may go
out again immediately if the original cause of the power outage was not
corrected. For example, if a tree branch falls across a high voltage
line, power will be cut but the automatic circuit breakers will then
attempt to restore is perhaps 30 seconds or a couple minutes later.
There may be several retries, each being hard on your electronics!

It is best if electronic equipment is totally unplugged until power is back
up and stable.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the Feedback Form in the FAQs.

thank you for the reply

 

[[email protected]]

They can occur randomly for many reasons ( solar activity), failure at
a switching station, etc. Power surges are most likely to occur during
an electrical storm. I've repaired several TV's due to lightening
damage.

 

[Tanya]

| hi,
| are power surges more likely to occur following a power outage (right
| when the power is restored)?

Yes. Always a good idea to turn everything off except a light.

| or do they occur randomly

Yes, depending on where you live.

N

thanks for the reply...
if one lives in an area where surges are common randomly can one assume
pretty certainly that following an outage there will be a power surge?

 

[Tanya]

They can occur randomly for many reasons ( solar activity), failure at
a switching station, etc. Power surges are most likely to occur during
an electrical storm. I've repaired several TV's due to lightening
damage.

hi and thanks
if there's a surge in one house (same fuseBox) does it hit all outlets
(assuming there are no surge protectors) or is it possible for it to
damage things from only 1 outlet?
(assuming the equipment is the same per outlet)

 

[James Sweet]

hi and thanks
if there's a surge in one house (same fuseBox) does it hit all outlets
(assuming there are no surge protectors) or is it possible for it to
damage things from only 1 outlet?
(assuming the equipment is the same per outlet)

Power surges can enter through power, phone, cable, antenna, or any other
lines into the house. Sometimes equipment will be damaged, sometimes not, it
depends on too many things to predict. Surge protectors can help to some
extent but they're largely useless, your best bet is to unplug expensive
equipment during storms and outages.

 

[NSM]

| NSM wrote:
|
| > | > | hi,
| > | are power surges more likely to occur following a power outage (right
| > | when the power is restored)?
| >
| > Yes. Always a good idea to turn everything off except a light.
| >
| > | or do they occur randomly
| >
| > Yes, depending on where you live.
| >
| > N
|
| thanks for the reply...
| if one lives in an area where surges are common randomly can one assume
| pretty certainly that following an outage there will be a power surge?

It's much more likely than not. I've seen them bounce the voltage up very
high before they get it all stabilised. If you don't want to lose the item,
turn it off.

N (Electrician)

 

[w_tom]

To understand destructive transients, learn the principles
that Ben Franklin demonstrated in 1752. Destructive
transients seek earth ground. If they find a path to earth
via your appliances, then you suffer damage.

Sometimes, such destructive transients create power
failures. Damage occurs before the power failure. But many
then assume the power restoration, instead, caused electronics
damage. When power is restored, everything wants maximum
power. Therefore power comes back slowly. It is not
destructive. Power does not surge in like a wave. It comes
back like a lake refilling during rain.

Do not assume "surge protector = surge protection". They
are separate devices. All electronics requires surge
protection - so that protection already inside the appliance
will not be overwhelmed. But a surge protector does not
provide that protection. A surge protector is one way we
connect incoming utilities to surge protection.

Your phone line already has a protector provided free by
your telco. But it does nothing effective without the less
than 10 foot connection to protection. Notice the two
separate devices. A protector connects less than 10 foot to
earth ground - the protection.

Your CATV requires no protector. It must first connect
direct (hard wired) to earth ground before entering the
building.

AC electric is the most common source of destructive
transients. Unfortunately we still build new homes as if the
transistor did not exist. We still don't connect every AC
electric wire to earth ground via a 'whole house' protector.
Such devices cost about $1 per protected appliance. And
again, it will only be as effective as its earth ground - as
Ben Franklin demonstrated in 1752.

At best, you are there only one hour in three to protect
your appliances. Furthermore, you cannot disconnect many that
could suffer transient damage - dishwasher, GFCI receptacles,
smoke detector, clock radio. You need 'whole house' protector
AND earth ground that meets or exceeds post 1990 NEC
requirements. The protector will only be as effective as its
earth ground.

A final point. Any protection that works at the appliance
is already inside the appliance. This protection assumes you
have earthed the most destructive transients before they can
enter the building. A plug-in protector adjacent to a
computer can even contribute to damage of that powered off
computer. In part because a surge does not strike, do damage
and halt. First a surge takes a complete path. IOW there
must be both an incoming and outgoing path through the
appliance. Only then does something inside that appliance
fail. To be surge damaged, the appliance must be part of a
complete circuit. So mythical plug-in protectors will have
you believe it will stop what three miles of air could not.

Again, don't fall for myths that "surge protector = surge
protection". A surge protector is only as effective as the
earth ground. All incoming utilities must connect to the same
single point earth ground. Protection is only as effective as
that earth ground. Ineffective protectors, instead, avoid
mentioning any of this.

 

[Tanya]

Power surges can enter through power, phone, cable, antenna, or any other
lines into the house. Sometimes equipment will be damaged, sometimes not, it
depends on too many things to predict. Surge protectors can help to some
extent but they're largely useless, your best bet is to unplug expensive
equipment during storms and outages.

thank you for replying
sincerely
Tanya

 

[Tanya]

thank you very much for explaining this!
sincerely
Tanya

To understand destructive transients, learn the principles
that Ben Franklin demonstrated in 1752. Destructive
transients seek earth ground. If they find a path to earth
via your appliances, then you suffer damage.

Sometimes, such destructive transients create power
failures. Damage occurs before the power failure. But many
then assume the power restoration, instead, caused electronics
damage. When power is restored, everything wants maximum
power. Therefore power comes back slowly. It is not
destructive. Power does not surge in like a wave. It comes
back like a lake refilling during rain.

Do not assume "surge protector = surge protection". They
are separate devices. All electronics requires surge
protection - so that protection already inside the appliance
will not be overwhelmed. But a surge protector does not
provide that protection. A surge protector is one way we
connect incoming utilities to surge protection.

Your phone line already has a protector provided free by
your telco. But it does nothing effective without the less
than 10 foot connection to protection. Notice the two
separate devices. A protector connects less than 10 foot to
earth ground - the protection.

Your CATV requires no protector. It must first connect
direct (hard wired) to earth ground before entering the
building.

AC electric is the most common source of destructive
transients. Unfortunately we still build new homes as if the
transistor did not exist. We still don't connect every AC
electric wire to earth ground via a 'whole house' protector.
Such devices cost about $1 per protected appliance. And
again, it will only be as effective as its earth ground - as
Ben Franklin demonstrated in 1752.

At best, you are there only one hour in three to protect
your appliances. Furthermore, you cannot disconnect many that
could suffer transient damage - dishwasher, GFCI receptacles,
smoke detector, clock radio. You need 'whole house' protector
AND earth ground that meets or exceeds post 1990 NEC
requirements. The protector will only be as effective as its
earth ground.

A final point. Any protection that works at the appliance
is already inside the appliance. This protection assumes you
have earthed the most destructive transients before they can
enter the building. A plug-in protector adjacent to a
computer can even contribute to damage of that powered off
computer. In part because a surge does not strike, do damage
and halt. First a surge takes a complete path. IOW there
must be both an incoming and outgoing path through the
appliance. Only then does something inside that appliance
fail. To be surge damaged, the appliance must be part of a
complete circuit. So mythical plug-in protectors will have
you believe it will stop what three miles of air could not.

Again, don't fall for myths that "surge protector = surge
protection". A surge protector is only as effective as the
earth ground. All incoming utilities must connect to the same
single point earth ground. Protection is only as effective as
that earth ground. Ineffective protectors, instead, avoid
mentioning any of this.

<snip>

 

[Tanya]

| NSM wrote:
|
| > | > | hi,
| > | are power surges more likely to occur following a power outage (right
| > | when the power is restored)?
| >
| > Yes. Always a good idea to turn everything off except a light.
| >
| > | or do they occur randomly
| >
| > Yes, depending on where you live.
| >
| > N
|
| thanks for the reply...
| if one lives in an area where surges are common randomly can one assume
| pretty certainly that following an outage there will be a power surge?

It's much more likely than not. I've seen them bounce the voltage up very
high before they get it all stabilised. If you don't want to lose the item,
turn it off.

N (Electrician)

thank you for the reply
sincerely
Tanya