Thank you Jon. Sorry about the newbie questions, but then, those sockets are not meant for DIY, right? Also, most homes in Spain don't have an earth/ground... Not sure how it's referred to in english but security is provided by the main differential. How does that affect security and DIY?
Thank you again.
I've not been to Spain often, but the wall sockets I plugged into all had a third pin for the Protective Earth (PE).
You need the PE to blow the fuse when a fault takes mains to the enclosure/chassis.
If there is no PE, the fuse does not rupture and the enclosure/chassis stays Live until you touch it. Only after you have been blown across the room does the fuse blow because you became the escape route for the fault current to return to source.
You need the PE to blow the fuse when a fault takes mains to the enclosure/chassis.
If there is no PE, the fuse does not rupture and the enclosure/chassis stays Live until you touch it. Only after you have been blown across the room does the fuse blow because you became the escape route for the fault current to return to source.
Yes, what you point out is the Schuko socket type. But most of the electrical devices work using the IEC C8 cables, thus the question pointed out in OP. Also, even though it may look like crazy, the fact we have Schuko sockets does not mean that particular house has an earth.
I am reading about it but don't manage to find more clarity on this.
Thank you again
I have been trying to find the rule about not connecting a Protective Earth/Safety Ground to a Class II chassis.
The ClassII double insulated "package" is designed, manufactured and guaranteed as a complete unit.
No one, other than the manufacturer or their authorised service centre is allowed to modify that "package".
This will be written into the regulations for the design and manufacture of a ClassII product.
No one, other than the manufacturer or their authorised service centre is allowed to modify that "package".
This will be written into the regulations for the design and manufacture of a ClassII product.
Till now I built most line level (so low power) devices with this C8 connector. Drawback is the need for a separate fuse holder. I only connect PE to the power amplifier chassis by means of a fused IEC connector. In the power amplifier I reference audio GND to PE. I must also tell I am an experienced builder and I am aware of safety issues. I am also the only user of the equipment. Using no PE with a metal case really is a time consuming endeavour. It takes a lot of plastic sheet material and heat shrink tube, insulation rings etc. If you know you are a sloppy builder please do not even bother. The mains part is more work than any other case work ! Any possible leakage current should be considered and taken into account. Recently I got hold of slow curing transformer epoxy and maybe I will use this stuff to mold in the 230V inlet and everything related. Here devices less than 5VA don't need PE if appropriate safety rules are followed.
In the past I have encountered many (mainly UK built) devices that each had audio GND connected to PE directly. Hum and ground loops were standard. Because of this I have put many hours in modifying such equipment to a usable level. Some of them had PE connected to chassis but less than 4 mm clearance between case and mains voltage ?! Some of them were wired safely with regards to PE but apart from that they were quite unreliable and/or plain dangerous (MF A-1 comes too mind). There is some kind of hysterical feeling there about making everything so safe that audio quality goes down the drain (sorry AndrewT). The ridiculous banana connectors that don't accept banana plugs (!) and the BFA connectors are nice examples. I have worked with many a british contractor in the recent past and safety is so overdone that working is near impossible with several guys overseeing the work of one doing the actual work. It was me that was hysterically laughing when one of those guys told me that I could not take my screwdrivers to a roof (and ordered a hydraulic elevator for that)
Must be a union thing and awareness is that the world should follow their way of working (or non working if you prefer).
There is a middle way as said. Builder should be very aware and experienced though ! Safety is of utmost importance but audio quality is of prime importance in the light of the purpose of the device.
* Please note that there are several A brand manufacturers that produce C8 connectors but some are better isolated than others. Avoid the cheap chinese versions ! Alway check distance between mains voltage carrying contacts to chassis.
In the past I have encountered many (mainly UK built) devices that each had audio GND connected to PE directly. Hum and ground loops were standard. Because of this I have put many hours in modifying such equipment to a usable level. Some of them had PE connected to chassis but less than 4 mm clearance between case and mains voltage ?! Some of them were wired safely with regards to PE but apart from that they were quite unreliable and/or plain dangerous (MF A-1 comes too mind). There is some kind of hysterical feeling there about making everything so safe that audio quality goes down the drain (sorry AndrewT). The ridiculous banana connectors that don't accept banana plugs (!) and the BFA connectors are nice examples. I have worked with many a british contractor in the recent past and safety is so overdone that working is near impossible with several guys overseeing the work of one doing the actual work. It was me that was hysterically laughing when one of those guys told me that I could not take my screwdrivers to a roof (and ordered a hydraulic elevator for that)
Must be a union thing and awareness is that the world should follow their way of working (or non working if you prefer).There is a middle way as said. Builder should be very aware and experienced though ! Safety is of utmost importance but audio quality is of prime importance in the light of the purpose of the device.
* Please note that there are several A brand manufacturers that produce C8 connectors but some are better isolated than others. Avoid the cheap chinese versions ! Alway check distance between mains voltage carrying contacts to chassis.
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Hi all and thank you for all the answers.
Please let me clarify this upfront. I'd rather be too cautious than too dead, thus the questions. So not worried about hum or noises at the moment, just safety. With that being said:
1. When people use 3 pins plugs and internal grounding: what happens if something breaks and the house/flat/building does not have a proper ground? (yes, even if the plug is 3 pins). Because it looks to me there is an apparent-only sensation of safety from everyone assuming 3 pins means there is always a proper ground.
2. If I follow the double insulation scenario, I assume that even if I managed to double insulate all cables and cover PSUs and use many fuses (where?), there'd still be potential threats if something break: on/off switch? LM3886 screwed to the case external heatsink? ... Or should I assume in this case (using IEC C8) NOTHING must be connected to the chassis?
Thank you again!
Please let me clarify this upfront. I'd rather be too cautious than too dead, thus the questions. So not worried about hum or noises at the moment, just safety. With that being said:
1. When people use 3 pins plugs and internal grounding: what happens if something breaks and the house/flat/building does not have a proper ground? (yes, even if the plug is 3 pins). Because it looks to me there is an apparent-only sensation of safety from everyone assuming 3 pins means there is always a proper ground.
2. If I follow the double insulation scenario, I assume that even if I managed to double insulate all cables and cover PSUs and use many fuses (where?), there'd still be potential threats if something break: on/off switch? LM3886 screwed to the case external heatsink? ... Or should I assume in this case (using IEC C8) NOTHING must be connected to the chassis?
Thank you again!
1.Very dangerous ! Never use PE stuff in ungrounded outlets as half of the mains voltage will be on the case of the device in many cases. If the house has no PE please add PE wiring + RCD (or better, have it done by a certified electrician) for your and your families safety. I have seen this in very old houses and in countries where time stood still. Please draw a cap from L to PE and one from N to PE and now check what happens if you plug the device in without PE connection. Right : half the mains voltage is at the chassis/case because of the caps ! This often noticed when touches a computer case in such situations. The tingling feeling ! Now suppose one of these caps (always the one from L to PE ) shorts because of bad quality....
2. You don't connect anything to chassis except (maybe) audio GND with a series resistor in a very rare case... You make sure there is NO possibility a loose L or N wire can ever touch chassis or any metal part in a lifetime.
) shorts because of bad quality....2. You don't connect anything to chassis except (maybe) audio GND with a series resistor in a very rare case... You make sure there is NO possibility a loose L or N wire can ever touch chassis or any metal part in a lifetime.
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All houses have RCD but not all of them have PE. And even if you have the 3 wires including ground, this is not a proof your building will have a proper earth/ground for sure. Thus my newbie question about false sensation of safety.
Does "nothing" also mean avoid screwing the LM3886 to the chassis heatsink?
If you live in a modern West European country there are several laws and regulations that are tools to ensure electrical safety is well regarded and neglect is punished by law if electricians make a mess of it. Proof is a strange item to laymen or end users when there are strict standards. The certified company that installs/connects stuff should know what is safe and they should measure everything when the house is ready to be habited. They also make a report of that with test results. You could ask yourself what happens if PE is disconnected at the side of the power company. Then don't go outside !! If the system is being adhered to there will be a general set of standards and a general safe standard way of working so quality will be standard with the odd exceptions.
If nothing should be connected then also the LM chip should be mounted isolated. If the heatsink is connected to the case/chassis then please use an IEC connect with PE connected to the case/chassis.
*** This is the safer case which I forgot to mention: if you are sure you have PE done right in your home you can use IEC inlets and connect PE to the case but leave audio GND still floating or "lifted" the safe way. UK people will start shouting but here this is fully safe and legal. They will come up with unlikely disaster scenarios which we don't experience *** You see, Europe is far from being a place with general standards. However using PE for protect people is more or less a standard in almost any European country.
If nothing should be connected then also the LM chip should be mounted isolated. If the heatsink is connected to the case/chassis then please use an IEC connect with PE connected to the case/chassis.
*** This is the safer case which I forgot to mention: if you are sure you have PE done right in your home you can use IEC inlets and connect PE to the case but leave audio GND still floating or "lifted" the safe way. UK people will start shouting but here this is fully safe and legal. They will come up with unlikely disaster scenarios which we don't experience *** You see, Europe is far from being a place with general standards. However using PE for protect people is more or less a standard in almost any European country.
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For starters: PE is by law and for safety. At least here it is, both in Germany and in the Netherlands. I can not speak for other countries. There is not a single electrician that does not know or does not use PE as education and law/regulations are quite clear. They know where one starts to look when things go wrong. The system is strict and electricians correct faults they see by instinct or they will make a remark as they have responsibility for peoples safety. In extreme cases they refuse to switch on an installation when they consider it unsafe. I deal with them very often and have high esteem for their craftsmanship.
As a layman you should find out what regulations and laws are where you live and talk to some electricians or such companies to check how safety is done. Then have your house installation checked and measured for safety by a known good certified company and update to 2017 standards if necessary. Then they will measure and verify their work (ask for a report). In most countries laws have changed to this being the responsibility and task for the house owner. Experience learns that most installations start OK but in the years following "handy people" start changing things....When the house is sold the new owner (layman in most cases) just assumes everything is OK. For example: here (Germany) insurance won't pay a Euro when one has done uncertified electrical work and the house burns because of that. Don't exaggerate with being dead. We all die, it better not be because one lives in a banana republic where there is no PE
So take some action and don't wait for the house installation to become safe by itself. It won't. BTW this also counts when you use natural gas. When in doubt or because of age simply have the installation checked. Most will frown and don't do a thing (costs money !!) which is why governments want to put responsibility at the house owner.
As a layman you should find out what regulations and laws are where you live and talk to some electricians or such companies to check how safety is done. Then have your house installation checked and measured for safety by a known good certified company and update to 2017 standards if necessary. Then they will measure and verify their work (ask for a report). In most countries laws have changed to this being the responsibility and task for the house owner. Experience learns that most installations start OK but in the years following "handy people" start changing things....When the house is sold the new owner (layman in most cases) just assumes everything is OK. For example: here (Germany) insurance won't pay a Euro when one has done uncertified electrical work and the house burns because of that. Don't exaggerate with being dead. We all die, it better not be because one lives in a banana republic where there is no PE
So take some action and don't wait for the house installation to become safe by itself. It won't. BTW this also counts when you use natural gas. When in doubt or because of age simply have the installation checked. Most will frown and don't do a thing (costs money !!) which is why governments want to put responsibility at the house owner.
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hey
thank you for all the info. sure, when i said "I'd rather be too cautious than too dead" i really meant it, i'd rather not even start the project than kill me or someone else.
now, PE is not granted in my building. i know because some plugs will have 2 wires, some 3. so, i cannot rely on it.
i suppose i (only?) have 3 options (*):
1. use IEC C8 (without ground) in a plastic/wood case (no aluminium) and double insulate internal cables, cover PSU's, ... (anything else?)
OR
2. use laptop type PSU's only (one for DAC, one for AMP, one for whatever else), avoiding AC power into the case. would this be enough to be safe in case of something breaking?
OR
3. not to build anything
thank you
* making the flat installation checked being important as well
thank you for all the info. sure, when i said "I'd rather be too cautious than too dead" i really meant it, i'd rather not even start the project than kill me or someone else.
now, PE is not granted in my building. i know because some plugs will have 2 wires, some 3. so, i cannot rely on it.
i suppose i (only?) have 3 options (*):
1. use IEC C8 (without ground) in a plastic/wood case (no aluminium) and double insulate internal cables, cover PSU's, ... (anything else?)
OR
2. use laptop type PSU's only (one for DAC, one for AMP, one for whatever else), avoiding AC power into the case. would this be enough to be safe in case of something breaking?
OR
3. not to build anything
thank you
* making the flat installation checked being important as well
Thank you again Andrew!
So, I understand you are suggesting to follow my item 2 in the list above: I can use "laptop type PSUs" since those are all ClassII. The problem with that approach is I would need 3 of them (DAC, AMP, Source selector) at the very least, up to 5 or 6 (pre for Phono, Vu Meter, ...).
Would item 1 in the list above be considered safe (or safe-ish)? That was: "use IEC C8 (without ground) in a plastic/wood case (no aluminium) and double insulate internal cables, cover PSU's, ... (anything else?)"
Thank you again
Lap top PSUs can come in either ClassI, or ClassII
The ClassI must have a PE since these are not designed and manufacured and guaranteed to be safe for all foreseeable accidents, that ClassII is guaranteed to be safe for.
And no you your last you must use a PE for all ClassI equipment.
You cannot convert a ClassI product to ClassII by sticking it inside an insulating box !
The ClassI must have a PE since these are not designed and manufacured and guaranteed to be safe for all foreseeable accidents, that ClassII is guaranteed to be safe for.
And no you your last you must use a PE for all ClassI equipment.
You cannot convert a ClassI product to ClassII by sticking it inside an insulating box !
Ah OK, so no "laptop PSU" but specifically "class II PSU". Noted. Two more questions for now, please bear with me, trying to learn how not to get dead
1. Looking for it, but are there commercial toroidal transformers with more than one secondary that comply to Class II? Seen this one, not sure this is what we are talking about: http://www.reo.co.uk/product/254
2. In my situation (no PE at home), using a Class II PSU, would I still need to avoid anything to be connected to chassis?
Thank you again
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