Open Service Neutral GFCI/RCD Detector

[mbrooke]

Why is TT common in Europe? Are they saving on transformer grounding conductor?

Good question. Honestly, I do not know for sure. However, I do know TT supplies are recommended where the neutral conductor is likely to be disconnected. In trailer parks for example, only TN-S and TT is permitted because a broken PEN or CNE can be very dangerous. In dairy farms and chicken coops TT is good because any voltage drop along the neutral does not place itself on the grounding system. Cows are very sensitive to stray voltage. In France TT is used universally.

Or why didn't they ground one leg (of the two hots) to become the neutral?

One leg grounded. Often its 230/400Y, with homes receiving a neutral and hot, businesses 3 hots and a neutral.

Norway is IT, but thats another story.

In my country. Since 99.99% of homes don't have local grounding electrode and no ground wire direct to transformer, then it's like we are also TT. Or what do you refer to those without even local grounding electrode (are these installed in all homes in Europe with TT transmission system?).

At best it sounds like a system without any grounding. At worst a TT that has not properly been implemented.


TT systems in Europe have a grounding electrode system at the building. The wire from the earth driven rods or plates goes to the ground bar in the panel. All the circuits are RCD protected in some way as that is what will remove a fault. Ground rods vary in resistance, and 2 out of 3 times do not pass enough current to trip a regular breaker or fuse.


I do not know what part of the Philippines you are from, but the Philippine electrical code requires that each structure have a service neutral, one or more ground rods, and a grounding system within the building. Its based on the American NEC, often word for word. Technically everything that you describe is a dozen of more code violations.

 

[tersh]

Good question. Honestly, I do not know for sure. However, I do know TT supplies are recommended where the neutral conductor is likely to be disconnected. In trailer parks for example, only TN-S and TT is permitted because a broken PEN or CNE can be very dangerous. In dairy farms and chicken coops TT is good because any voltage drop along the neutral does not place itself on the grounding system. Cows are very sensitive to stray voltage. In France TT is used universally.




One leg grounded. Often its 230/400Y, with homes receiving a neutral and hot, businesses 3 hots and a neutral.

Norway is IT, but thats another story.





At best it sounds like a system without any grounding. At worst a TT that has not properly been implemented.


TT systems in Europe have a grounding electrode system at the building. The wire from the earth driven rods or plates goes to the ground bar in the panel. All the circuits are RCD protected in some way as that is what will remove a fault. Ground rods vary in resistance, and 2 out of 3 times do not pass enough current to trip a regular breaker or fuse.


I do not know what part of the Philippines you are from, but the Philippine electrical code requires that each structure have a service neutral, one or more ground rods, and a grounding system within the building. Its based on the American NEC, often word for word. Technically everything that you describe is a dozen of more code violations.

My parents house without grounding is in the capital in manila. So even in capital manila, 99.99% of homes don't have any grounding. As I said. This is because our appliances don't have any grounding, so contractors don't put any grounding. And most of the time city hall officials were paid $20 to avoid inspection. They earn $10 a day only (to raise 5 family members without other source of income) they would always get the $20. It's standard operating procedure for construction in the Philippines. Corruption is the middle name.

Anyway. Without any local electrode ground rod installed in a home. How many currents can pass via the metal panel to back concrete wall (where panel is attached) to the soil, and to the transformer which has pole ground rod below the pole? Can it reach 500mA? So if you have 100mA RCA, it can trip even without any local electrode grounding rod presence?

 

[mbrooke]

My parents house without grounding is in the capital in manila. So even in capital manila, 99.99% of homes don't have any grounding. As I said. This is because our appliances don't have any grounding, so contractors don't put any grounding. And most of the time city hall officials were paid $20 to avoid inspection. They earn $10 a day only (to raise 5 family members without other source of income) they would always get the $20. It's standard operating procedure for construction in the Philippines. Corruption is the middle name.

Ahhhh, ok, now that makes more sense. And trust me, we have corruption here to, just in other areas.


With all said and done, I personally would put GFCI/GFP/RCD protection on the circuits and call it good. Best thing next to an EGC.

Anyway. Without any local electrode ground rod installed in a home. How many currents can pass via the metal panel to back concrete wall (where panel is attached) to the soil, and to the transformer which has pole ground rod below the pole? Can it reach 500mA? So if you have 100mA RCA, it can trip even without any local electrode grounding rod presence?

I'd have to be there to measure it, but I would assume 500ma is very well possible. Concrete, wet soil, the use of a mutli grounded neutral on the high voltage making more then one rod at the power company... All gives a good path to hurt people.

If you have an RCD, and something energizes like a fridge, and someone touches it passing current through them into the floor to the earth- it will cause the RCD to trip as soon as it goes above the rating of the RCD. You do not need ground rods at the home to protect people in that scenario.

 

[tersh]

Ahhhh, ok, now that makes more sense. And trust me, we have corruption here to, just in other areas.


With all said and done, I personally would put GFCI/GFP/RCD protection on the circuits and call it good. Best thing next to an EGC.



I'd have to be there to measure it, but I would assume 500ma is very well possible. Concrete, wet soil, the use of a mutli grounded neutral on the high voltage making more then one rod at the power company... All gives a good path to hurt people.

If you have an RCD, and something energizes like a fridge, and someone touches it passing current through them into the floor to the earth- it will cause the RCD to trip as soon as it goes above the rating of the RCD. You do not need ground rods at the home to protect people in that scenario.

For concrete like concrete wall inside the house. Usually how many ampere can pass from concrete to concrete only? What's the top ampere it can pass. Dry concrete and not wet.

The RCD will not protect a fridge but will protect a subpanel in case hot wire touches panel metal enclosure or the bus bar basepan melts and ibus bar touches the panel metal enclosure/chassis. The sub panel will house 6 Siemens 2-pole 240v GFCI breakers with 5mA personal protection.

If each Siemens GFCI is 5mA. Then 5 x 6 =30mA. So maybe a 50mA RCD would trip if hot wires the enclosure?

The Siemens panel will be opened often to reset any Siemens GFCI that is why ground fault protection via the RCD needed.

If the idea is feasible. Of course it will be installed by qualified electricians.

 

[mbrooke]

For concrete like concrete wall inside the house. Usually how many ampere can pass from concrete to concrete only? What's the top ampere it can pass. Dry concrete and not wet.

Honestly, I do not know for sure. But I would assume enough to harm. Remember that its not just concrete you have to worry about.

The RCD will not protect a fridge but will protect a subpanel in case hot wire touches panel metal enclosure or the bus bar basepan melts and ibus bar touches the panel metal enclosure/chassis. The sub panel will house 6 Siemens 2-pole 240v GFCI breakers with 5mA personal protection.

If each Siemens GFCI is 5mA. Then 5 x 6 =30mA. So maybe a 50mA RCD would trip if hot wires the enclosure?

The Siemens panel will be opened often to reset any Siemens GFCI that is why ground fault protection via the RCD needed.

If the idea is feasible. Of course it will be installed by qualified electricians.

You mean an RCD main for this panel plus the 5ma Siemens? Sure, that will work. I would recommend a delayed trip for the 50ma so a branch fault does not trip both the 5ma and 50ma, but its not needed.

BTW- I don't know how qualified other electricians are- but you yourself have good knowledge and are asking all the right questions

 

[Adamjamma]

Ahhhh, ok, now that makes more sense. And trust me, we have corruption here to, just in other areas.


With all said and done, I personally would put GFCI/GFP/RCD protection on the circuits and call it good. Best thing next to an EGC.



I'd have to be there to measure it, but I would assume 500ma is very well possible. Concrete, wet soil, the use of a mutli grounded neutral on the high voltage making more then one rod at the power company... All gives a good path to hurt people.

If you have an RCD, and something energizes like a fridge, and someone touches it passing current through them into the floor to the earth- it will cause the RCD to trip as soon as it goes above the rating of the RCD. You do not need ground rods at the home to protect people in that scenario.

But.. you do need at least thethirty milliamperes of the eu RCD and really should use the lower value USA gfci, which is four to six milliamperes...

 

[mbrooke]

But.. you do need at least thethirty milliamperes of the eu RCD and really should use the lower value USA gfci, which is four to six milliamperes...

Correct.

 

[Adamjamma]

Also, do not add up the milliamperes to try to figure other values... the reason for using individual gfci is to speed up the reaction for each circuit. There are lag style gfci for the fridge, or you could use a 30 milliamperes for the fridge...
the UK uses one 30 milliamperes RCD to protect five to six breakers under it... that does not mean it is as effective as the US individual gfci breakers, but that for a monetary and legal basis the UK has decided that this method is effective.
The US panel, and your panel if the photos are your panel, do not lend themselves to the same method so you must consider the use of GFCI rather than RCD. So, as you afford it, replace each circuit breaker with a gfci breaker. That will hopefully reduce the touch potential and increase the safety factors.

 

[tersh]

Also, do not add up the milliamperes to try to figure other values... the reason for using individual gfci is to speed up the reaction for each circuit. There are lag style gfci for the fridge, or you could use a 30 milliamperes for the fridge...
the UK uses one 30 milliamperes RCD to protect five to six breakers under it... that does not mean it is as effective as the US individual gfci breakers, but that for a monetary and legal basis the UK has decided that this method is effective.
The US panel, and your panel if the photos are your panel, do not lend themselves to the same method so you must consider the use of GFCI rather than RCD. So, as you afford it, replace each circuit breaker with a gfci breaker. That will hopefully reduce the touch potential and increase the safety factors.

I'll put 6 pcs of Siemens QF230A 2-pole GFCI 240v (5mA tripping) Breakers bought at amazon https://www.amazon.com/Siemens-QF23...544685892&sr=8-1&keywords=siemens+qf230a+gfci

So the 6 breaker Siemens panel will use all Siemens GFCI Breakers with 5mA.

Say. Is there any US RCD that is rated at 30mA? Since 5mA x 6 = 30mA and all GFCI breakers won't trip at same time then a 30mA RCD 100A would be sufficient?

No. My individual GFCI won't power any refrigerator. I will use 2 pcs 500va medical grade fully electrostatic shield isolation transformer for the 2 Refrigerators. All the 6 pcs of Siemens GFCI 2-pole 240v breakers will just be connected to all the outlets in the house including bathroom, bedroom, sala and every possible outlet except refrigerators and airconditioning whose breakers are in the main panel that is seldom opened.

 

[Adamjamma]

I would not bother with an extra RCD on the incoming as you already have the gfci in place at 5 to 6 milliamperes each... so adding any to the main breaker would just create problems. Ideally, if you only have six circuits, you put the gfci on each circuit and you are done.
in the case of the fridge, if the plug point is accessible you could put a gfci outlet there, replacing the current outlet, and thus be right next to the fridge with the reset point.
Dont try to overthink everything. The UK has gotten to the point that AFCi type circuits are optional but recommended... but GFCI circuits are required everywhere in a residence, including lighting...

The USA seems to be making more of a requirement for AFCI.. perhaps because more buildings are stuck frame construction compared to the UK concrete and steel construction or brick construction...brick and mortar in UK can get mortgages at way better interest rates than any of the alternatives, including the steel frame buildings..lol..

 

[Adamjamma]

Oh, and for your fridge circuits, could you not just put them on gfci breakers as well, and use commercially available surge protectors at the outlet? I mean, surge strips should be available that plug into the outlet and you then plug the fridge into, because I use them here in the UK and in the Caribbean. The UK ones for 230 work fine on my stuff in the Caribbean that is US 240 wired so as far as the surge protectors go, I have no problems with US line to line 240 or UK line to neutral 240 on the 240 rated surge protectors... personal experience from returning residents... not tested in labs...lol

so I would just get the appropriate 240 volt surge protectors for the individual appliances...

 

[tersh]

Oh, and for your fridge circuits, could you not just put them on gfci breakers as well, and use commercially available surge protectors at the outlet? I mean, surge strips should be available that plug into the outlet and you then plug the fridge into, because I use them here in the UK and in the Caribbean. The UK ones for 230 work fine on my stuff in the Caribbean that is US 240 wired so as far as the surge protectors go, I have no problems with US line to line 240 or UK line to neutral 240 on the 240 rated surge protectors... personal experience from returning residents... not tested in labs...lol

so I would just get the appropriate 240 volt surge protectors for the individual appliances...

My Fridge trips on the 6mA generic unlisted meiji 240v GFCI receptacle I pictured earlier. Some say during defrosting. It's 10 year old fridge whose picture I also shared earlier. So I won't use GFCI on fridge but isolation transformer. And no I don't need to put surge protector for it. It's just for my home TV and CCTV and iPhone charger, the fridge doesn't need surge protection (nothing would get fried there, we never used it for the past 50 years).

So RCD 30mA trip current is ok (or must it be 50mA)? Should I get with model with delay? Also must it be without electronics? Can you push the white test button even on the versions without electronic?
.

 

[tersh]

I would not bother with an extra RCD on the incoming as you already have the gfci in place at 5 to 6 milliamperes each... so adding any to the main breaker would just create problems. Ideally, if you only have six circuits, you put the gfci on each circuit and you are done.
in the case of the fridge, if the plug point is accessible you could put a gfci outlet there, replacing the current outlet, and thus be right next to the fridge with the reset point.
Dont try to overthink everything. The UK has gotten to the point that AFCi type circuits are optional but recommended... but GFCI circuits are required everywhere in a residence, including lighting...

The USA seems to be making more of a requirement for AFCI.. perhaps because more buildings are stuck frame construction compared to the UK concrete and steel construction or brick construction...brick and mortar in UK can get mortgages at way better interest rates than any of the alternatives, including the steel frame buildings..lol..

I need to add an RCD before the Siemens subpanel housing 6 GFCI breakers 5mA because what if the hot wire inside the subpanel shorts to the enclosure (or the bus bar melted and short the subpanel chassis)? We don't have any neutral or ground wire to the transformer centertap and we don't have any local electrode grounding rod. Image TT like classificaiton. The main panel is seldom touched.. but my parents need to open the Siemens subpanel whenever a GFCI needs to be reset, so I need to put RCD before the subpanel just to disable the entire subpanel (with only outlet loads) in case there is shorting of hot wire to subpanel metal chassis. Just tell me if RCD 30mA is enough or 50mA? With Delay? With electronics or not? Do those without electronics have the white push button testing feature?

Anyway. I just received my 500va fully shielded medical isolation transformer to be used on the 200va (or so) refrigerator so as to shield it from the utility ground http://catalog.triadmagnetics.com/Asset/VPM240-2080.pdf

It is enough and we won't put the fridge in the GFCi because as explained in last message, it trips during defrosting.

My qualified technician will put it in listed enclosure.

 

[mbrooke]

Make sure the fridge is actually 200va, some units when defrosting go higher. Mine actually pulls 12 amps, LOL

 

[tersh]

Make sure the fridge is actually 200va, some units when defrosting go higher. Mine actually pulls 12 amps, LOL

This is the spec. Whats the maximum defrosting ampere you think?

 

[romex jockey]

You've an interesting situation tersh.

......can we assume you've circuitry equipment grounding conductors throughout the structure?

~RJ~

 

[mbrooke]

This is the spec. Whats the maximum defrosting ampere you think?

Looks good from here

 

[winnie]

You've an interesting situation tersh.

......can we assume you've circuitry equipment grounding conductors throughout the structure?

~RJ~

He has explicitly stated that there are no EGCs in the wiring, and no neutral-earth bond in his service, and no neutral conductor to his service, and that these defects are not practical to correct.

He is essentially inventing band-aids to cover the poor installation practices used in his country.

-Jon

 

[tersh]

He has explicitly stated that there are no EGCs in the wiring, and no neutral-earth bond in his service, and no neutral conductor to his service, and that these defects are not practical to correct.

He is essentially inventing band-aids to cover the poor installation practices used in his country.

-Jon

Maybe the Europeans are also doing band-aids for the TT system?

I just dropped by the home now and saw the plugs from the generic made in china Meiji GFCI receptacle transferred to another outlet. My parent told me it was because the GFCI kept tripping. It's connected to two rice cookers. Also I read this feedback from a European. He said something that made me wonder. Are 240v rice cooker prone to tripping that is why the Europe increases the threshold to 30mA? (Does your US rice cooker also keep tripping on the 5mA GFCI or not?) quoting him:

"Here in Europe, RCDs are usually installed to protect entire circuits, not just single socket outlets. Each appliance may leak a new mA to ground, even if it is working correctly. Electronic devices with suppression capacitors, and devices with mineral insulated heating elements (such as cookers and water heaters) are usually the worst for this.

So using a 5mA or 10mA RCD will probably result in nuisance tripping.So for protecting people from electrocution, 30mA was chosen as a compromise. The 30mA is the maximum at which the RCD must trip. Manufacturing variances mean that some will trip at lower currents.

Earthing (grounding) arrangements vary wildly across Europe. Here in the UK we still use three different arrangements - TT, TN-S and TN-C-S.

If it is a TT installation, the supplier provides no ground, and the customer must use an earth rod, which is not connected to the supply neutral. Even a dead short between live and the consumer's earth will not pass enough current to blow the supply fuse. So it is common to fit a 100mA time-delayed RCD to the incoming supply, which will trip instead. In large commercial installations, a 100mA RCD may still nuisance trip. So it may be necessary to increase the RCD to 300mA or more. Note that these RCDs are there to detect and clear faults, not to protect people from electrocution.

100mA or more RCDs are sometimes also used where long cable runs are necessary, and the time to clear the fault by a fuse blowing or circuit breaker tripping may be too long.

European 230V RCDs will have four terminals - live in, live out, neutral in and neutral out. There is no provision for two phases, plus neutral. So there is no guarantee that an RCD connected only across the two phases would detect a fault current leaking to neutral or ground."​

 

[ptonsparky]

Typically when an item trips.the GFCI we do not increase the trip level. The item is faulty. Throw it out.