Open Service Neutral GFCI/RCD Detector

[tersh]

Ok. If you have a universal power supply that can accept 88v to 264v. Isn't it if you use a 120v SPD with VPR of 500v. It's more protective than using a 240v SPD with VPR of 1200?

The logic is this. You can only get lower VPR (Voltage Protection Rating) by having lower MCOV (Maximum Continuous Operating Voltage). So Europe and China with their 230v system. Their SPD VPR would be higher. Does it mean their equipments are not so protected compared to US?

My solution for 240v ac system is to use 240-120v step down transformer to take advantage of US 120v SPDs. Does this make sense and gives better protection especially when you are using a 88v-265v universal power supply (that can't accept overvoltage above 300v) on a sensitive Honeywell fire alarm system?

Hope you can clarify this confusing issue once and for all. Thank you.

 

[GoldDigger]

The logic is this. You can only get lower VPR (Voltage Protection Rating) by having lower MCOV (Maximum Continuous Operating Voltage). So Europe and China with their 230v system. Their SPD VPR would be higher. Does it mean their equipments are not so protected compared to US?

My solution for 240v ac system is to use 240-120v step down transformer to take advantage of US 120v SPDs. Does this make sense and gives better protection especially when you are using a 88v-265v universal power supply (that can't accept overvoltage above 300v) on a sensitive Honeywell fire alarm system?

Hope you can clarify this confusing issue once and for all. Thank you.

What I am saying is that putting an SPD on the far side of a transformer from the equipment it is protecting will not work. The resistance of the transformer will limit the fault current that the SPD can absorb from the high side of the transformer.
On the other hand if you use a transformer to drive both the protected load and the SPD, you will indeed be taking full advantage of the SPD and will also get additional protection based on the impedance of the transformer limiting the fault current that gets to the load and SPD from a fault on the high voltage side. I had not really been considering that possibility.

 

[tersh]

What I am saying is that putting an SPD on the far side of a transformer from the equipment it is protecting will not work. The resistance of the transformer will limit the fault current that the SPD can absorb from the high side of the transformer.
On the other hand if you use a transformer to drive both the protected load and the SPD, you will indeed be taking full advantage of the SPD and will also get additional protection based on the impedance of the transformer limiting the fault current that gets to the load and SPD from a fault on the high voltage side. I had not really been considering that possibility.

Yes. This latter is what I've been using all along. In the following. The 240v-120v step down isolation transformer is driving the 120v Leviton surge protector that gives protection to a universal power supply TV and router (both using 100-240v switching adaptor or power system)

What I was asking is what if the Europeans would use similar setup of 240-120v step down Isolation Transformer that would drive the 120v SPD and universal power supply equipment (88v to 265v). It would produce lower VPR and would be more protective than using 240v SPD, isn't it?

I have NOT considered the scenario where you use 240v SPD and use 240-120v step down transformer after it. It won't work because the VPR of 240v is still high and this can pass through the transformer. So I wasn't referring to this.

 

[ptonsparky]

Do you actually need the additional clamping if all your equipment is rated at 240V?

 

[tersh]

Do you actually need the additional clamping if all your equipment is rated at 240V?

My Honeywell Fire alarm system uses the Meanwell power supply with this specs:

See:https://www.meanwell.com/webapp/product/search.aspx?prod=RS-50

It says "Withstand 300VAC surge input for 5 seconds"​

So a lower VPR 120v would be more effective. Isn't it. With 240v SPD, it has VPR of 1200 volts!

 

[ptonsparky]

My Honeywell Fire alarm system uses the Meanwell power supply with this specs:

See:https://www.meanwell.com/webapp/product/search.aspx?prod=RS-50

It says "Withstand 300VAC surge input for 5 seconds"​

So a lower VPR 120v would be more effective. Isn't it. With 240v SPD, it has VPR of 1200 volts!

What is the cost of this item? What is the estimated cost of downtime should this item fail?

 

[winnie]

What you have done: 240V supply to 120V isolation transformer to 120V rated SPD to 'universal' devices being protected will improve the _line to line_ protection provided by the surge protected device.

Weather it actually improves over all safety or over all improves device protection is another question.

I will repeat what I have said in other threads; code is about practical safeguarding, not _perfect_ safeguarding. The reason for _practical_ is because you can always make things safer and can always improve performance, but only if you spend more resources. At some point those resources are better spent elsewhere.

I really believe that you are focusing huge amounts of energy on small pieces of the entire puzzle.

Look at your picture; you have a plug in transformer...is it really an isolation transformer or is it a more common 240V to 120V autotransformer? Then look at the rats nest of wires. I think that you have simultaneously improved the protection provided by the SPD and increased the risk of fire from a short circuit or someone simply tripping on your wiring.

Look back at the picture of the panel mounted SPDs. The wiring is single wire (not cable with an outer sheath) routed in 'ENT' (thin wall flexible plastic tubing, we call it smurf tube here because it is usually blue) going through a hole in the metal enclosure with no fitting or protection from the sharp edges. If your electrician did that then your electrician should be fired. Again: maybe an increase in protection from surges, but a decrease in other aspects of system safety.

You are spending time and money on tiny pieces of the system and ignoring basic mechanical improvements in your systems.

-Jon

 

[tersh]

What you have done: 240V supply to 120V isolation transformer to 120V rated SPD to 'universal' devices being protected will improve the _line to line_ protection provided by the surge protected device.

Weather it actually improves over all safety or over all improves device protection is another question.

I will repeat what I have said in other threads; code is about practical safeguarding, not _perfect_ safeguarding. The reason for _practical_ is because you can always make things safer and can always improve performance, but only if you spend more resources. At some point those resources are better spent elsewhere.

I really believe that you are focusing huge amounts of energy on small pieces of the entire puzzle.

Look at your picture; you have a plug in transformer...is it really an isolation transformer or is it a more common 240V to 120V autotransformer? Then look at the rats nest of wires. I think that you have simultaneously improved the protection provided by the SPD and increased the risk of fire from a short circuit or someone simply tripping on your wiring.

Look back at the picture of the panel mounted SPDs. The wiring is single wire (not cable with an outer sheath) routed in 'ENT' (thin wall flexible plastic tubing, we call it smurf tube here because it is usually blue) going through a hole in the metal enclosure with no fitting or protection from the sharp edges. If your electrician did that then your electrician should be fired. Again: maybe an increase in protection from surges, but a decrease in other aspects of system safety.

You are spending time and money on tiny pieces of the system and ignoring basic mechanical improvements in your systems.

-Jon

They were installed by the electrician of the Prosurge SPD local supplier who was also a licensed electrical engineer. Someone else also mentioned the sharp edges and I told him to fix it and they put plastic tube holder. The picture was older. Also it's just temporary. I will let the electrician removed all of it soon.

I'm doing all this just to learn and review my lessons 20 years ago. It was not really for any practical reason (I could use 240v SPD and that's it) but just to gain knowledge of it all.

You see, the Prosurge distributor who is licensed electrical engineer didn't even know the difference between VPR and MCOV. That was why he put 320v MCOV to the 120v line to neutral in the office building. So I'm learning in order to at least point out to him and others to study all of it more carefully.

 

[tersh]

What is the cost of this item? What is the estimated cost of downtime should this item fail?

The Honeywell fire alarm system and smoke detectors costs about $2000. Downtime could reach a week.

It has no surge protection for a year. My IBM XT has no surge protection for 30 years and still working.

Actually all this is just to learn too.. and to review old lessons. I had many electrical subjects but forgot most of them. It would be a waste if I don't review them now.

 

[tersh]

What I am saying is that putting an SPD on the far side of a transformer from the equipment it is protecting will not work. The resistance of the transformer will limit the fault current that the SPD can absorb from the high side of the transformer.
On the other hand if you use a transformer to drive both the protected load and the SPD, you will indeed be taking full advantage of the SPD and will also get additional protection based on the impedance of the transformer limiting the fault current that gets to the load and SPD from a fault on the high voltage side. I had not really been considering that possibility.

This is very important concept that all suppliers of SPDs in my country don't know. Hence I need to know this at least to inform them and for my own building.

Remember I told you in my type 3 SPD beside equipment, there is a 240-120v step down isolation transformer that drive both the 120v SPD and 120v Honeywell equipment (with worldwide Universal Power Supply). This is optimum, but I realized yesterday that since I have a type 2 SPD at main panel. Then the type 2 SPD would be seeing the high impedance of the transformer 10 meters away and won't work?

Or let's take this illustration:

Are you saying that the second type 2 SPD at middle would only discharge surges depending on the resistance of the load at the right And it doesn't act independent?

This is very important. Many think they act independent. Even my country distributor of SPDs think it's independent. This is why the distributor who is a licensed electrical engineer hasn't warned me about the transformer driving the type 3 SPD effect on the main panel type 2 SPD.

So either I must remove the transformer/120v SPD combo at equipment and replace with 240v SPD or remove the type 2 SPD at main panel? Which do you think must be removed for better protection? My type 2 SPD at main panel is a Siemens First Surge 140,000A SPD and connected this way at the office building.

10 meters away from it is a 500va Hammond 240-120v step down transformer driving a type 3 120v Leviton 36kA Surge protector strip.

First. Please confirm, the Siemens First Surge type 2 SPD at main panel can't work as it can feel the 500va Hammond transformer 10 meters away from it (driving the 120 Leviton above), right? This is the most important question. If yes. Then I need to remove either of them so kindly address and clarify or emphasize the point as I'm not sure this is exactly what you have in mind without you saying yes or no. Many thanks!

 

[tersh]

Tersh,

Referring to the middle schematic diagram-- your theory holds. However, in the real world-- electronics/electricity doesn't behave exactly what you have envisioned.

The instance you cut the wire that is grounded (the one indicated with an “X”) with color blue-- the current passing through the inductor that is being compared with the top (brown) wire will see a change in current. During this split-second exigency, power will also be lost.


With its blue wire losing its connection to the lower inductor -- which WAS connected to ground—the RCD will not have the chance to compare this current that it was seeing before the wire was severed.

For this RCD to function without false alarm, it needs a wee time delay to ignore tripping caused by transient disturbances. . . otherwise you will be inundated with nuisance shutdowns. It needs to discriminate between the good and the bad signal.

Now, you can argue that the (MEN) multiple earth neutral will provide the continuity of power through the multiple ground connection, and (hopefully) enable the RCD to function and open the contacts.

The problem with this is, earth is an unreliable conductor whose resistance could vary depending on the moisture content.
And besides, it is an unorthodox even insane- not an acceptable and totally unsound engineering practice.

If you had driven these rods in the infiniteness of moist ground like a rice field in the Philippines, you will probably see a uniform impedance, but it will still not pass muster in a sensible engineering practice.

Now, the third diagram with the REVERSED HOT to NEUTRAL scenario is even worst.

If you reverse the BLUE and BROWN as indicated in your drawing -- you would end up connecting the hot brown wire (and while at the same time) keeping the MEN connected the way they are-- you'd be creating a short circuit.

Try tracing it systematically and you'll see what I'm talking about.

Note:
I'm not endorsing anything that could compromise safety. Hiring a multi- licensed electrician will not absolve you from any consequences that may arise should you go ahead with what you think would achieve your goal.

Don't call Jacoby and Myers telling them that Myspark, told you how it should be done. I'm just answering your question.

Mabuhay!

Myspark. I found out there are RCDs that can open when the source lost its power. For example. Read this:

Therefore, the open service neutral detector can indeed work using RCDs that open from power failure.

 

[tersh]

according to both Seimens and Hager have told me that I cannot use their RCDs on USA style 240 volt circuits because there would be too many false trips due to the way the 240 volts is created. but they also have given me the spec sheets to use the same rcds and rcbos on 110 volt circuits with a normal neutral. So, apparently, there is a difference and they said most of the tripping problems happen not from imbalance in the live wire as much as feedback from ...other live wires being used...

Again, I am not totally understanding it but they also said that unless you use a 2 pole plus neutral RCD or RCBO false tripping will occur and often from other circuits interference not the actual circuit, if one is using one live to neutral position in order to create a higher voltage. But, a 2pole plus neutral is not a normal, in Europe, configuration.
Now, since I am a student and not understanding all the theory, all I can do is say what I have been told in my several letters and emails to them...

I have asked several people about this. They said the toroids in the RCDs or RCBOs can only detect current inbalances. So in theory the RCDs and RCBOs should work in the USA 240v (red and black) system. Can you please ask your Siemens contacts the exact reason about these feedback (and some references)? Is your contact from the technical support or just someone working at the Siemens office. It's so perflexing.

Or better yet. Has anyone heard of anyone successfully using Europe RCD 1P+N in the USA 240v system.. just for sake of discussions and technical understanding of it?

 

[tersh]

This is very important concept that all suppliers of SPDs in my country don't know. Hence I need to know this at least to inform them and for my own building.

Remember I told you in my type 3 SPD beside equipment, there is a 240-120v step down isolation transformer that drive both the 120v SPD and 120v Honeywell equipment (with worldwide Universal Power Supply). This is optimum, but I realized yesterday that since I have a type 2 SPD at main panel. Then the type 2 SPD would be seeing the high impedance of the transformer 10 meters away and won't work?

Or let's take this illustration:

Are you saying that the second type 2 SPD at middle would only discharge surges depending on the resistance of the load at the right And it doesn't act independent?

This is very important. Many think they act independent. Even my country distributor of SPDs think it's independent. This is why the distributor who is a licensed electrical engineer hasn't warned me about the transformer driving the type 3 SPD effect on the main panel type 2 SPD.

So either I must remove the transformer/120v SPD combo at equipment and replace with 240v SPD or remove the type 2 SPD at main panel? Which do you think must be removed for better protection? My type 2 SPD at main panel is a Siemens First Surge 140,000A SPD and connected this way at the office building.

10 meters away from it is a 500va Hammond 240-120v step down transformer driving a type 3 120v Leviton 36kA Surge protector strip.

First. Please confirm, the Siemens First Surge type 2 SPD at main panel can't work as it can feel the 500va Hammond transformer 10 meters away from it (driving the 120 Leviton above), right? This is the most important question. If yes. Then I need to remove either of them so kindly address and clarify or emphasize the point as I'm not sure this is exactly what you have in mind without you saying yes or no. Many thanks!

The bottom line that you emphasized is that the impedance or resistance between equipment and SPD must be low. But what if the equipment itself has high impedance or resistance?

I know that divider action is what creates the low voltage across the MOV because of low current. So if the impedance of the source wire and the load is the same, then the MOV won't work at all?

Kindly let me know because I need to let electrician remove either the type 2 SPD or type 3 SPD (with transformer) tomorrow because one may be useless. Thanks.

 

[tersh]

The bottom line that you emphasized is that the impedance or resistance between equipment and SPD must be low. But what if the equipment itself has high impedance or resistance?

I know that divider action is what creates the low voltage across the MOV because of low current. So if the impedance of the source wire and the load is the same, then the MOV won't work at all?

Kindly let me know because I need to let electrician remove either the type 2 SPD or type 3 SPD (with transformer) tomorrow because one may be useless. Thanks.

Reading your past messages again and again and reviewing my lessons in college 25 years ago. When the impedance is high at the transformer near type 3 SPD. It will attract the current away from the first SPD or source impedance. Or by divider action, the current will be more or less equally divided. Since the SPD at type 3 is working too (after the transformer). I think the setup will still work.

 

[romex jockey]

.

Or better yet. Has anyone heard of anyone successfully using Europe RCD 1P+N in the USA 240v system.. just for sake of discussions and technical understanding of it?

That would be any toroid based ocpd in the us....1,2&3P tersh

Interesting thread, seems you've a cross breed system

as to noodle/no noodle .....i'm reminded of sall the hot tub applications (as well as theads) desribing our 2P+N GFCI's . either with....or w/o noodle....

~RJ~

 

[tersh]

That would be any toroid based ocpd in the us....1,2&3P tersh

Interesting thread, seems you've a cross breed system

as to noodle/no noodle .....i'm reminded of sall the hot tub applications (as well as theads) desribing our 2P+N GFCI's . either with....or w/o noodle....

~RJ~

I was just perflexed by Adamjamma insistence that Europe 1P+N RCDs can't be used in the US 240v system because of some feedback in the circuit. Actually in my country these Euro models are being sold for our similarly centertapped grounded neutral 240v system. https://new.abb.com/low-voltage/products/system-pro-m/residual-current-devices/rcbo

What can cause the feedback? If I buy the ABB RCD locally and install these. The company wouldn't refund them if I keep complaining that it keeps tripping. So want to get to the bottom of this circuit feedback thing before I buy some.

 

[romex jockey]

Fundamentally ,it's the toroid sensing an imbalance tersh

Objectively, RCD's and GFI's are similar ,in that they both incorporate a toriod.

So....the big Q might be, how does a 'leak to ground' return to the serving Xformer?

Which begs the earthing system design....TT? .....TN-C-S?

~RJ~

 

[tersh]

Fundamentally ,it's the toroid sensing an imbalance tersh

Objectively, RCD's and GFI's are similar ,in that they both incorporate a toriod.

So....the big Q might be, how does a 'leak to ground' return to the serving Xformer?

Which begs the earthing system design....TT? .....TN-C-S?

~RJ~

In the US. It passes via soil (local electrode to pole ground rod) and via the neural conductor straight to centertap. How about in Europe. Is there country there that passes soil to soil (or TT only)? In the Philippines, since we don't use local ground rod and no ground wire to centertap. It's concrete to soil to utility pole. I wonder if this has relation to manner of death by electrocution. In the US, is electrocution mostly occur at home or outside. In our country. Even though our appliances don't have EGC. Electrocution doesn't occur from it but mostly from direct contact to live wire, either from dangling wire or defective wires. For example.

"

"Family of 5 die of electrocution in their Pangasinan house

DAGUPAN CITY — A family of five died on Monday night (Aug. 15) after they were electrocuted inside their house in a village in Malasiqui town in Pangasinan province.

The bodies of couple Ariel Colarco and Rochelle Mendoza and their children, Gieann, Henry and Michael were found sprawled on the floor of their house in Barangay Bacundao East at about 8:05 p.m., said Supt. Roland Sacyat, Malasiqui police chief.

Sacyat said Rochelle may have been trying to install a clothesline inside the house at that time because she was holding a galvanized iron wire when she was found.

Investigators said a portion of the metal wire may have snagged a badly plugged appliance on the wall.

Sacyat said two of Rochelle’s children, who were beside her, may have attempted to pull her to save her but died in the process.

The bodies of Ariel and another child were found in another spot of the house holding the other end of the wire."


They could have been saved by a $30 GFCI. In the USA. Do all household have GFCI? In my 1000 friends relatives, etc. Only I have GFCI. All of them doesn't know what it does.
​

 

[ptonsparky]

All except the oldest have at least some GFCI protection. Even here a mishap as you describe could be possible on a concrete floor that is in a finished area not requiring GFCI protection.

 

[Sahib]

Regular education of public in developing countries about dangers of using electricity by POCO, for example, distributing pamphlets etc., might make them more alert and avoid fatalities.