Power surges

[Forkinhades]

your up early Xy

[Crossy]

your up early Xy

Hmmm, you too mate

We're always up at 4.30, head into town at about 6.00 to avoid the traffic.

[Forkinhades]

Golf day

[Naam]

Gonsalviz

Last year, power surges caused, I guess by lightning cost me in excess of 40,000 baht.

I was looking for a whole house surge protector. At one shop a guy guy told me that there was no such thing. I know that is wrong.

i paid through my nose, not because of surges but because of low voltage which caused to fry starting relays of aircons and pumps. problem was solved 100% by having the gadget (see picture below) built. paid Baht 31k about 7 years ago. the system works both ways (voltage too high and voltage too low) by switching off the individual phase.

a lightning strike in the phone line fried 3 modem/routers. 2 hubs and a motherboard. protected each phone line with surge protectors where they enter my home. don't know the brand, price around 650 Baht each.

[Crossy]

A question Naam, have the life indicators on your surge arrestors ever indicated anything other than 100% OK?

We have the same unit (single phase) and even after a major event it hasn't changed (I replaced the cartridge anyway).

[Naam]

A question Naam, have the life indicators on your surge arrestors ever indicated anything other than 100% OK?

We have the same unit (single phase) and even after a major event it hasn't changed (I replaced the cartridge anyway).

i replaced one of them. any other surges must have been caught by the automatic relays or the manual breakers (expression?). a trip of one of the latter happens every 2 or 3 months.

[Forkinhades]

^ expression MCB : Minature Circuit Breaker, These can be reset

HRC : High Rupture Capacity : These would need to be replaced.

[RichCor]

it wasn't connected in that picture but its on the bottom right now.

Pic previously referred to had a connection bottom right ie earth unless these old eyes were playing more tricks, have now just added an arrow.

surge2.jpg

Trying to determine exactly where all the wires go in a Panel Box is difficult enough when you're standing in front of it, with good light, and the correct wire color used. Trying to do similar from a flash photo with poor depth is even more difficult.

From the original photo I noticed only Wire Pairs, the Ground would have made it a Third.

Luckily I have yankee99 saying the Ground Wire was added after the photo had been taken.

[Crossy]

Sorry Guys if asking dumb questions, but I am a total noob if it comes to Electricity.

I have read somewhere that if you turn off the main breaker before a surge hits, the surge will not be able to reach your equipment, but I have also read that the surge will be able to jump and still can reach your equipment (if you don't have a Surge protector)

Which one is true.

Thanks.

BOTH

Turning off the mains will certainly stop the majority of induced surges getting at your equipment, it will also stop the electricity getting there too, hope you like sitting in the dark. A quality surge arrestor or ten will stop the majority of these surges doing significant damage and you get to keep the lights on.

BUT. A direct hit to the supply lines will hop across the 4mm or so contact gap as if is wasn't there ... fried kit even if you have an arrestor.

Best option for really close storms is to unplug sensitive gear (don't forget the antenna / dish / phone line).

[Forkinhades]

What about a few contactors Xy? controlled via a single switch? located next to DB?

[Gonsalviz]

it wasn't connected in that picture but its on the bottom right now.

Pic previously referred to had a connection bottom right ie earth unless these old eyes were playing more tricks, have now just added an arrow.

surge2.jpg

Trying to determine exactly where all the wires go in a Panel Box is difficult enough when you're standing in front of it, with good light, and the correct wire color used. Trying to do similar from a flash photo with poor depth is even more difficult.

From the original photo I noticed only Wire Pairs, the Ground would have made it a Third.

Luckily I have yankee99 saying the Ground Wire was added after the photo had been taken.

All of my C/B's have the line running through the L/H side and the neutral running through right side. Are your reversed from that? Difficult to tell with no wire colors showing. I doubt it matters butI just want to verify.

If I were to connect mine the way yours are, I would be running the line L-N and N-L at the surge protector.

[yankee99]

I didnt know that it about a specific side for line or neutral but if you look at the top left youll see white tape indicating the neutral side is the lh in this pic....Which goes to the neutral of the surge protector..

[Gonsalviz]

I didnt know that it about a specific side for line or neutral but if you look at the top left youll see white tape indicating the neutral side is the lh in this pic....Which goes to the neutral of the surge protector..

Now I see the white tape. The Thai's spececifically have all Line wires on the left side of the of the breakers. I have so many Big breakers in my box it is hard to keep track of them.

The main input from PEA runs to a 100 amp breaker breaker then runs directly to an 80 amp breaker that powers the house and then branches off to another 80 amp breaker that runs the 2 water pumps.

Must be some massive water pumps.

[Crossy]

What about a few contactors Xy? controlled via a single switch? located next to DB?

Actually one of those Chang knife switches would have a nice big contact gap.

It would be a pretty big surge to get across that.

[Forkinhades]

^ Indeed any good isolator 32A and above would work nice.

Wonder what the insurance issues would be with or without said devices in place.

[carlyai]

On the thread that was closed and refered to this thread, there was talk about air conditioner boards being destroyed due to power problems.

I just had 3 new inverter air conditioners installed yesterday and, although I have earth wiring throughout the house, the air con guy insisted that with the inverter type air conditioners each unit had to be connected to an earth spike, which he drove in next to the units.

From what I think he said was that with the inverter air conditioners if you don't have the earth spke, and you have power problems, the units will be destroyed. Not too sure if he meant pcb's or what.

[Forkinhades]

You need to install MOVs (Metal Oxide Varistor) or TVSSs (Transient Voltage Surge Suppressor) to protect your equipment, the earth rods will not protect your equipment.

You can get some cheap MOVs and install them at each AC unit. Or you can get a whole house unit which is sited inside your electrical distribution unit.

[Crossy]

On the thread that was closed and refered to this thread, there was talk about air conditioner boards being destroyed due to power problems.

I just had 3 new inverter air conditioners installed yesterday and, although I have earth wiring throughout the house, the air con guy insisted that with the inverter type air conditioners each unit had to be connected to an earth spike, which he drove in next to the units.

From what I think he said was that with the inverter air conditioners if you don't have the earth spke, and you have power problems, the units will be destroyed. Not too sure if he meant pcb's or what.

Did he also connect the existing house ground as well as the spikes??

There is no requirement for local ground spikes at inverter (or any other A/C) but it's possible he was covering all bases and it cannot do any harm.

If you have regular power issues, than adding a whole-house surge arrestor also cannot do any harm.

[bankruatsteve]

Now I gotta ask... if there are regular power issues (supply?) why wouldn't an AVR be the recommendation?

[Forkinhades]

I assumed the power problems were spikes due to electrical storms, but an AVR would also protect against undervoltage and overvoltage with a +15% and -25% range.

[carlyai]

Guys,

i have been searching all over for a surge protector (like the one in the picture from yankee99) but the only thing I can find is this:

http://www.wipelectric.com/product_desc.php?id_code=18

Is this good enough for whole house protection ? Or is this something completely different?

That is not a surge arrestor!

It is an over/under voltage device that will disconnect your supply when it goes outside the normal range, usually for several seconds.

We have one that triggers the genset when the mains goes out of range (invariably low).

You need something like this http://www.ebay.co.uk/itm/ABB-440V-2-KV-65-KA-DOUBLE-2-POLE-DIN-RAIL-SURGE-ARRESTOR-OVR-N1-65-440S-/281018036783?pt=LH_DefaultDomain_3&hash=item416dfaf22f

or this http://www.ebay.co.uk/itm/Dehn-Dehnguard-T275-Single-Pole-Surge-Arrester-A900-650-275V-20A-/150959806024?pt=LH_DefaultDomain_3&hash=item2325e7d648

Sorry for being sooo dumb, but the over/under voltage device W-OP2 has a wiring diagram that, at present, I can't figure out. Maybe it's the Leo from last night, but where do you wire the pump? There are two wiring diagram pictures on the device. In the diagram L1 and N and N linked to terminal 11 go to the device, but what terminals on the device, do I wire to the pump as there has to be a relay contact in the pump power input line.

[Crossy]

Sorry for being sooo dumb, but the over/under voltage device W-OP2 has a wiring diagram that, at present, I can't figure out. Maybe it's the Leo from last night, but where do you wire the pump? There are two wiring diagram pictures on the device. In the diagram L1 and N and N linked to terminal 11 go to the device, but what terminals on the device, do I wire to the pump as there has to be a relay contact in the pump power input line.

On the diagram K1 is a 220V contactor or relay that controls the pump. F3 is the motor overload unit (not needed on the small motors we're taking about).

The relay in the W-OP2 is rated at 5A so small pumps would be OK between pin 14 and Neutral. Link pins 11 - 21 and 14 - 24 to parallel up the relay contacts for longer life / more current handling.

We have one of these that fits better in a DIN consumer unit http://www.ebay.co.uk/itm/Adjustable-Over-Under-Voltage-Protective-Relay-/221381033800?pt=LH_DefaultDomain_3&hash=item338b567f48 but it still needs a relay / contactor to handle the main load.

[carlyai]

Sorry for being sooo dumb, but the over/under voltage device W-OP2 has a wiring diagram that, at present, I can't figure out. Maybe it's the Leo from last night, but where do you wire the pump? There are two wiring diagram pictures on the device. In the diagram L1 and N and N linked to terminal 11 go to the device, but what terminals on the device, do I wire to the pump as there has to be a relay contact in the pump power input line.

On the diagram K1 is a 220V contactor or relay that controls the pump. F3 is the motor overload unit (not needed on the small motors we're taking about).

The relay in the W-OP2 is rated at 5A so small pumps would be OK between pin 14 and Neutral. Link pins 11 - 21 and 14 - 24 to parallel up the relay contacts for longer life / more current handling.

We have one of these that fits better in a DIN consumer unit http://www.ebay.co.uk/itm/Adjustable-Over-Under-Voltage-Protective-Relay-/221381033800?pt=LH_DefaultDomain_3&hash=item338b567f48 but it still needs a relay / contactor to handle the main load.

That makes more sense. Thanks Crossy. So to wire it as per the diagram you have to buy the contactor K1 and the Overload relay F3 plus some fuses.

I see on the forum, that many people have these over/under voltage devices, so do they all wire them as Crossy has stated, or do they buy the contactors, etc?

Someone posted that 'they were easy to wire in' so I presumed everything was in the package or the device.

To buy the contactor K1 to go with the device, do I ask for a contacTER and show them the device?

As I am learning 'pumps ain't pumps', so the quoted wattage is 300 W so that's about a running current of 1.5 A, so I probably don't need the contacTER?

[Crossy]

It's a contactOR

For a small pump you should get away with a relay with a 220V coil, have a word with your local electrical emporium. Size the contacts assuming a starting current of full-load x 4.

No need for the overload unit for a pump, fuses not needed if the MCB will provide overload and short circuit protection.

EDIT Something like this http://www.ebay.co.uk/itm/JQX-38F-AC-220V-40A-11-Pin-3PDT-Coil-Power-Relay-Socket-/281046746158?pt=LH_DefaultDomain_3&hash=item416fb1042e I've used this seller in the past without issue.

[PattayaClub]

I have a Schneider QO-SPD225 panel mounted MOV rated at Imax 15kA. Can these things be "stacked"? In other words, if I plugged two of them onto the panel, would I have Imax 30kA of protection? Something else? No benefit to the second one?

[Crossy]

There is nothing to stop you adding another unit in parallel with the first, but it won't double your Imax.

These things have production tolerances and the one with the lower threshold voltage will always fire first, the other may never get a look in (depends upon just how different the trigger voltages are).

It does of course mean that when the first unit wears out and goes open the second is there to take over immediately, so there is some advantage to adding another if you have space (but don't feed them from the same breaker).

Also remember that Imax is the current the device can handle without damage, it will still clamp a much higher energy surge but may not recover.

In addition to the front end unit, I would scatter good quality plug-in units around your home to 'finish off' any remaining surges that get past the big beastie.

[PattayaClub]

There is nothing to stop you adding another unit in parallel with the first, but it won't double your Imax.

These things have production tolerances and the one with the lower threshold voltage will always fire first, the other may never get a look in (depends upon just how different the trigger voltages are).

It does of course mean that when the first unit wears out and goes open the second is there to take over immediately, so there is some advantage to adding another if you have space (but don't feed them from the same breaker).

Also remember that Imax is the current the device can handle without damage, it will still clamp a much higher energy surge but may not recover.

In addition to the front end unit, I would scatter good quality plug-in units around your home to 'finish off' any remaining surges that get past the big beastie.

I was intrigued by your post on another thread (closed) where you suggested putting 8kA varistors right on the appliances, downstream for the panel. It sounds like a great idea and I was about to order a handful of the little blue devils.

But I'm wondering, if I already have a 15kA MOV device in the panel, and the varistors with the lowest threshold fire first, does that mean the will the downstream varistors are going to blow out before the higher threshold unit in the panel even does anything?

I guess I do not really understand how these things work.

[PattayaClub]

It's a contactOR

For a small pump you should get away with a relay with a 220V coil, have a word with your local electrical emporium. Size the contacts assuming a starting current of full-load x 4.

No need for the overload unit for a pump, fuses not needed if the MCB will provide overload and short circuit protection.

EDIT Something like this http://www.ebay.co.uk/itm/JQX-38F-AC-220V-40A-11-Pin-3PDT-Coil-Power-Relay-Socket-/281046746158?pt=LH_DefaultDomain_3&hash=item416fb1042e I've used this seller in the past without issue.

I just bought a couple of these the other day from my local supplier in Phitsanulok. They had all different voltages and amperage ratings -- quite a comprehensive selection. I bought a couple 220V, 5 amp units to operate solenoid valves. They work great. Brand is Omron, made in China. Can't remember the cost, but not expensive.

Take a picture with you; that's what saved my bacon!

[Crossy]

But I'm wondering, if I already have a 15kA MOV device in the panel, and the varistors with the lowest threshold fire first, does that mean the will the downstream varistors are going to blow out before the higher threshold unit in the panel even does anything?

I guess I do not really understand how these things work.

It's all about timing.

MOVs are very fast, typically reacting to a fast rise-time surge in 50-60ns (1ns is 0.000000001 seconds).

The surge travels down the cable at a finite speed, in the order of 100-200ns per metre (it's hugely variable and could be significantly greater). By contrast light travels at about 3ns/m.

If your cable is, say, 10m between the front-end MOV and the smaller unit at your appliance, then the main MOV will have triggered a whole 950ns before the surge even reaches the smaller MOV which can then mop-up the bit that got through.

[PattayaClub]

But I'm wondering, if I already have a 15kA MOV device in the panel, and the varistors with the lowest threshold fire first, does that mean the will the downstream varistors are going to blow out before the higher threshold unit in the panel even does anything?

I guess I do not really understand how these things work.

It's all about timing.

MOVs are very fast, typically reacting to a fast rise-time surge in 50-60ns (1ns is 0.000000001 seconds).

The surge travels down the cable at a finite speed, in the order of 100-200ns per metre (it's hugely variable and could be significantly greater). By contrast light travels at about 3ns/m.

If your cable is, say, 10m between the front-end MOV and the smaller unit at your appliance, then the main MOV will have triggered a whole 950ns before the surge even reaches the smaller MOV which can then mop-up the bit that got through.

Thanks a million, Crossy. I can see I'll be putting these little devils all over the place. But one more varistor question while I have you on the line.

You showed how to wire them into, say and air conditioner, over on the other thread. But let's say I have a washing machine that is filled with electronics and cost more than the typical air conditioner. It is 18-20 meters of wire away from the MOV device in the panel and I want to protect it further with the onsite varistors. The washing machine is plugged into a two-receptacle wall outlet and has it's own circuit. It might be difficult to open up the washing machine and try to wire these things internally.

Could I rig up a three-prong plug with three varistors, connected as shown in the other thread and simply plug it into the vacant receptacle beside the washing machine plug? If so, rigging up a bunch of them and deploying them would be a nifty way to further protect every appliance and pump in the house.

Edited June 23, 2015 by PattayaClub