- Thread Starter
- #121
can u open that url?
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Circuit breaker - which to choose
- Thread starter roxor
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- Thread Starter
- #122
so you are suggesting that i should immediately use floating earth ie separate line for ground?
ah okay, in that case i will have to make rewire everything.
radix
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No, I'm not saying to float the earth. That has all sorts of other problems, as you can build up a charge on the case from the magnetic field.
The best thing would be to get a proper 3-conductor outlet. But I'd defer to someone who really knows consumer electronics safety about using it with a N+E bridge.
In regards the to link, it's probably home depot trying to do location-dependent service. Just google "gfci without ground."
Try this one.
GFCI vs GFI
Brush up on GFCI vs. AFCI, the uses of GFCI circuit breakers and outlets and where GFCI are required.
www.homedepot.com
I am copying the section on GFCI working without ground here:
Will a GFCI Work Without a Ground?
A ground is not required for a GFCI to function. GFCI devices work by detecting the current flowing from the hot to the neutral wires. Any imbalance trips the device, so a ground is not required. Older homes and buildings not designed to current electrical codes can still have GFCI protection.
GFCI outlets installed without a ground may not trip when inspected with a voltage tester, which do require grounds to work. The device can be tested with the test button integrated in the outlet.
To fully comply with NEC regulations, GFCI devices installed without grounds must be marked “GFCI Protected” and “No Equipment Ground” on the plate.
audio_tony
Addicted to Fun and Learning
In the UK most installations use the TN-C-S grounding system (earth to neutral).
Which country are you in, as the regulations for your country will state how your home should be grounded.
Please be careful about taking advice about grounding schemes and earth leakage detection using an earth leakage circuit breaker, as standards may vary from country to country.
An earth leakage breaker in the UK is rated to trip at 30mA (that means that if it detects 30mA of current flow to ground it will trip).
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JustJones
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This looks like North American type breaker and receptacle. I thought you are in EU ?
Contact a reputable local electrician and explain what's going on. I would hope they would know the appropriate breaker you need.
- Thread Starter
- #130
at the moment Czechia.
- Thread Starter
- #131
currently EU - Czechia.
ah u guys dont know what kind of ppl/ experts and technicians live here
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They used choke style power supply.
radix
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I'm going to speak about the USA, which is what I know.
Here, we get L1, L2, and N from the utility. It's 110-120V per L1 and L2, or 220-240V for a 4-wire system like a dryer or induction cooktop.
At the entry to the home, there is an earth ground, G, (a long copper rod in the ground). N is tied to G at that one place, the main service panel at the entry of the house. Every outlet gets L (either L1 or L2), N, and G. Sub-panels also keep N and G separate. In this setup, all current flows via L1/L2 and N.
In the old days, it was only 2-wire (L + N) per outlet. Or sometimes G would be tied to different ground rods under the house.
Under normal conditions, G carries no current to/from an outlet. If there is an electrical fault, current will be shunted to G. This causes GFCI breakers or outlets to trip. If there is not a G (you only have L and N), then the fault is usually via a poor person who touched something bad, or for example, if there is a short to the metal case and a person touches the metal case.
If you only have 2 conductors to an outlet in your building, that means they either floated G or tied G to N at the outlet. By floating G, I mean not connecting it to anything.
If a product is designed to have an earth ground, then floating G is likely dangerous. If it is a 2-wire consumer product designed for use without a G, then they have hopefully taken proper precautions to protect the consumer from a fault, like using a plastic or non-conductive case and controls.
There's a fair bit of engineering that goes into electrical safety of consumer products that I'm not very familiar with, so please don't take anything I say as a recommendation to do something.
If G is tied to N at the outlet, and you draw 100A inrush, that will create a voltage difference over your wire in the wall. If that 100A is on the ground terminal, then the metal case of your system will see that voltage. Let's say you have 0.5 ohms of wire in the wall. V=IR => V = 50V. It's super brief, but not safe, in my opinion. If G is floating, you might still induce a voltage in the metal case from the transformers.
So, if you are sure that your outlet only has 2 wires, not hot + neutral + ground, then you might want to ask an electrician in your area about getting a proper ground run. That will put the metal case at near 0V even when you have 100A running between hot + neutral.
audio_tony
Addicted to Fun and Learning
I searched for electrical regulations in Czechia and the closest I could find was this forum post from 2011
It looks as though whatever earthing system you have will be defined by the age of the building you live in.
What Earthing system do I have?
Hi, I live in the Czech Republic and I have an old consumer unit that needs updating, and on inspection, it has an unusual earthing system (possibly not unusual for the Czech Republic). Here is a basic diagram: It's a 3-phase system with a earth wire heading towards the ground ( I am...
www.diynot.com
radix
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See https://www.asutpp.com/pen-conductor.html
You need an electrician to look at how your specific outlets and panels are wired.
The TNC/TNCS and PEN/PE+N generally describe how the utility delivers power to the building. You can split a PEN to a PE+N at the main distribution panel. All you really care about is if a particular outlet has a current-carrying protective ground or a split non-current carrying protective ground.
You can have a PEN (where the N and PE and bridged) or a PE+N (where the PE and N are separate) depending on how it was wired. If you have a 2-conductor outlet, then its bridged. If you have a 2-conductor with exposed ground, then you have a separate PE return.
There's many ways buildings are wired and it changes over time. I would never trust a label on something much less an as-built plan. You need someone to look.
audio_tony
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There is no 'best' ground setup. The ground setup used should be in accordance with the rest of the building (if an apartment block) or according to current standards if a house.
radix
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If you have a large inrush current, then IMO a current carrying protective earth ground for a metal chassis is not ideal. It will build up a voltage during that period. Let's say you have 2mm (12 AWG) copper wire and the distance is 10m to the protective ground (just to make the math easier). 12 AWG wire will be about 5 ohms / 1000m, so you have 0.05 ohms in the wire. If the inrush current is 100A, then you have V=IR = 5V. In the previous example I gave, I had a much higher resistance. Maybe 5V is OK, maybe you'll fell it if you touch the case. Again, all those numbers are just an example. I do not know the wiring codes where you are, so it may not even be an option to switch your grounding. Or it may be you have to run all the way to the distribution panel and it is not economically practical.
3-phase is a totally different beast. Only specialized equipment uses 3-phase. You may very well have 3-phase coming in to the building that is then converted for used by individual branches. That's 220V per phase, or 400V between phases, so you could get massive power out of it. I believe in the EU, each single phase is simply one of the 3-phase loads (i.e. L1+N, L2+N, L3+N is 3 single phase loads). In the US, 3-phase to 1-phase requires a transformer if it's 480Y/277V not 208Y/120V. And it also depends on if it's 3-wire (delta) or 4-wire (wye) service. It gets complicated and is very dangerous.
As I've mentioned, I'm not an electrician so nothing I say should be considered advice (apart from where I say talk to an electrician!).
I would explain the situation to him: I have an amplifier with large toroidal transformers that seems to have a large inrush current, as it sometimes trips the breaker. Do I have a non-current carrying protective earth? if not, should I get one and how much $? Should I switch to a slower circuit breaker?
He should be able to inspect your panel and your outlet and let you know what can be done.
Have you inspected the fuses in the PSU, and are they the correct ones?
- Thread Starter
- #140
the guy was here ...
he said i have 2x25A or 1x25A option
He mentioned that main connect is TN-C and then he mentioned that ground will be as PEN where P/ E/ N each will be separate to the wall sockets..
is that okay?
thanks
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