Great video explaining clean earth systems. This is often a much misunderstood concept. This system is also often used for audio systems to help prevent hums in the system from circulating currents in the earthing system. The key is to not have any loops in the clean earth cabling. Must be ‘star’ or ‘radially’ wired. No ring circuits allowed!
@@G1ZQCArtwork Audio mains hum, interference and crosstalk is best reduced by using balanced audio cables. The telephone industry discovered this around 1885.
@@davidfaraday7963 I was immediately reminded of the single point of contact between telecoms earthing and mains earthing here, via the telecommunications reference conductor (TRC) the cabling for which is violet or red.
@@retrozmachine1189 Indeed. Or the way PCBs that have both analogue and digital circuitry on them will have segregated ground traces for the two even though both will be connected together at a common earth reference point.
I remember years ago at a newspaper site that the clean Earth had plug and socket arrangement whereby the Earth pin had been rotated 90 degrees meaning only kit with the plug could use the clean earth arrangement. Stopped cleaners and maintenance personnel using thoses dedicated circuits for hoovers or worse still drills.
It is all noise generated by switch mode power supplies with poor to no screening. Server Blade power supplies are extremely quiet, robustly made, virtually no EMC EMI at all. Radio Amateurs use them because they are noise free, so it can be done.
Hi, I hope you don't mind me wading in. As a fully qualified Radio Amateur for many years, I have some issues with this clean Earth arrangement. Firstly, the conductors are laid side by side in the ducting, so there is little to no chance of stopping EMC interference, as it is radiated by the cables, which will actually enhance the pick up of interference by acting as a receiver line. I can see no improvement whatsoever, unless you use a common mode choke method. Radio transmissions just travel between the gap, as if there was no gap, using capacitive and inductive coupling. In long Audio cable runs, it has been a well known fact that you need to run a balanced twin coaxial cable with the outer screen grounded at one end only. This stops EMC getting in, as it appears 90 degrees out of phase at the Audio desk, so is eliminated (see common mode choke theory). Secondly these are Voltage spikes not current spikes. You interchange these words far to frequently. Please replace the words current spikes with voltage spikes. Interference spikes are Voltage in nature, and appear on the cables as such, no matter where the Line curvature is. Further to, in a previous video eFIXX advocated using power line adapters for extending Wi-Fi, which introduces massive interference onto the power lines for many miles away from the property. This clean Earth system simply cannot work to reduce or eliminate EMC Voltage Spikes or noise. What am I missing.? David G1ZQC Lincolnshire.
I'm curious about it from and EM side as well. Isolated Ground as it's known this side of the Atlantic, is used in IT mainly for ensuring that all equipment outlets are connected to a common point, primarily for a common ground reference which is important for serial signaling, RS232 & RS485 where the voltage is small enough a voltage differential of a few volts can interfere with the signal. Less of an issue now that Ethernet & Fiber are the primary means, and they could care less about a ground reference voltages.
There are not supposed to be any equipment generating interference connected to the clean earth sockets, only your well designed noise sensitive equipment. @TheDrew2022: this is NOT an isolated ground. It's basically as if you fitted two separate electrical panels at your incoming meter and only connect sockets for "noisy" equipment to circuits on one of the panels. This means any current spikes in the noisy equipment will not generate induced current in the earth cable going to the sensitive equipment on the other panel.
I can’t understand in this day and age why things are designed to create all this hash and leakage . We are not in the best area for radio reception but some people can’t even listen to their radios due to all this hash , especially from some LED s plasma TVs etc. In the old days the GPO would be on you like a ton of bricks if you had anything that produced any form of noise Interference etc.
@@andysims4906 It's not really a case of designed to, it's a case of not designed not to. So much of the stuff that comes out of that certain country these days has zero RFI/EMC etc filtering at all. Even when it does you'd probably want it removed as the capacitors etc that should be safety rated are usually just standard grade components and cheap rubbish at that.
What you need to realise is the Two CPCs are inside the same conduit, so will pick up the EMC noise right in situ. It makes no difference if they run along side each other. RF radiation in the form of noisy Voltage spikes will bridge the gap like it is not there. Look up RF thermocouple for the theory. Clean Earths simply cannot work in the normal Physics world of RF.@@mrfrenzy.
Unfortunately I have come across sockets replaced on clean earth systems with standard sockets and the plastic pattress screws replaced with metal ones . In my many years of being a sparks ,Earthing arrangements are misunderstood or bodged or people don't believe and earth is important, we all seen earthing conductors missing or be cut off
We don't have any clean earth arrangements at my place of work, but it's interesting nevertheless.. there's probably some very interesting physics going on with that link between the general earth and the clean earth at 3:01 because to me, that just looks like the general MET and the clean MET are essentially the same thing at that linked point. I'm presuming any noise generated on the general MET takes the easiest route to earth and therefore doesn't affect the clean MET? I'd appreciate a bit more information on that part. And for anyone interested, the QR code means 'Internal>Level 02>2R13 Riser' , don't know why they don't just write that there instead of using a QR code though!
I thought the idea of having an MET and a clean MET bonded together at a single point further back towards the source was given way to more MESH bonded systems, like those described in BS EN 50310. For a local downstream example, in a comms room you would bond the distribution board for that room to the bonding earth bar that connects the I.T cabinets with dedicated bonds. You can also do this via a grid, however for most applications this is overkill.
You mention "IT Equipment" a lot in this video, but I've been in IT for 20+ years and have never once seen a Clean Earth anywhere amongst the equipment.
Question as we do these occasionally. Where running SWA's out to the feeder units would you (A)run a 4 core instead of 3 (B) run a separate single earth and cable tie with existing swa and use single earth as clean earth or... (C) use a 3 core swa, use the swa along with a bango/earthing nut as the dirty earth and the core within the swa as the clean earth. We often run a cable out of the board to an earth bar and do the connections there, not really sure if this is the correct way, to me it all goes to the same place so unsure of the point. Last point, sometimes we use the track to power wall sockets also. Whilst white plastic clean earth sockets are available, decorative metal sockets aren't, what do we do with the dirty earth? Connector block in back of box?
Hi mate thanks for the video. Clear as day, however I have a cabinet on site housing the clean earth bar as well as the safety earth bar and although the conductors going to these earth bars are physically separated, if I ring out the bars then I get continuity. The clean earth bar is raised on insulated points however the bolt within these insulated points is metal and it's used to mount the bar inside the panel. Is this perhaps the area at which the 2 bars are allowed to be connected?
I've been to TUV Fareham a few times to get products through EMC testing. I think your viewers would very much appreciate a visit to that site if they'd allow it (and it's not too far away from you).
Beautiful outlet product but why are they still even bothering installing Strip Connector Terminals with screws to wire in the cabling? Rather use 221-2411 WAGO inline connectors with 3 Way Snap In Base Plate Holders. ..
Are clean earth sockets sometimes colored red? because the powertrack for clean earth is red, so i might just ask. Some manufacturers provide sockets in Yellow and Red in my area, I never really.know why buildings used them
i have no idea about the electric wizardry (i'm a chemical technician) so i thought that this system is used for high end homes. Good to know you can use standard wiring. I'm saving Money so i can build an autarc home in the country side in croatia. A Family member repairs trams so he knows how to wire up stuff. My knowledge is limited to wiring Up LED 's and using wago 221's
Given the short cable runs and low number electrical items connected shouldn’t be a problem to identify what be the cause of emc? If for example were to install a high end home cinema then given its overall expense an extra cpc or two I doubt break the bank.
Clean earth systems can be usefull for electronics labs, music studios and even home hifi. Studios and Hifi usually use a clean earth as part of a (transformer) balanced power system and the earths are totally separate one clean earth for output and normal earth for the input these systems usually have an extra RCD on the output for safety (One on input side will not work) obviously the output is only for audio equipment and will have a non standard plug/socket arrangement. BTW EMC to an electronics enineer is ElectroMagnetic Compatability interference is EMI Electro Magnetic Interference
This might sound silly but could this not create a situation where there is a fault to an earth, the outer casing, which is only connected to the actual circuit via the main earth terminal and back again. That's an awfully long loop. If the socket run was connected with a tough cable rather than a metal connection could the whole thing run on one clean earth. Sorry but it's a long time since I've done commercial installs, 16th I think. 👴
@@efixx Probably unlikely but a fault between the line conductor and the outer casing. Probably doesn't make any difference, just seems odd to have an earth path not going through the board supplying the circuit.
Since potentials are relative and not absolute, this sounds like an awful idea since noise in the ground are due to opposite currents in the power lines. Just perform proper filtering and don’t allow equipment manufacturers to induce currents in the equipment ground. Currents should return though the other line or neutral.
Full free training module 👉 hub.efixx.co.uk/mt-underfloor-wiring
Great video explaining clean earth systems. This is often a much misunderstood concept.
This system is also often used for audio systems to help prevent hums in the system from circulating currents in the earthing system.
The key is to not have any loops in the clean earth cabling. Must be ‘star’ or ‘radially’ wired. No ring circuits allowed!
Audio mains hum is best reduced by dropping the Earth on the Audio cables at one end, or as you say, use radial circuits not rings.
@@G1ZQCArtwork Audio mains hum, interference and crosstalk is best reduced by using balanced audio cables. The telephone industry discovered this around 1885.
@@davidfaraday7963 I was immediately reminded of the single point of contact between telecoms earthing and mains earthing here, via the telecommunications reference conductor (TRC) the cabling for which is violet or red.
@@retrozmachine1189 Indeed. Or the way PCBs that have both analogue and digital circuitry on them will have segregated ground traces for the two even though both will be connected together at a common earth reference point.
Isolation transformer also remove harmonic distortion on an audio system.
This is a great lesson for someone trying to get into sound and communications
Thanks very much. 😊
You have to realise they are all connected. Clean Radio reception is being swamped in this EMC noise.@@efixx
The best lessons for sound applications come from audio engineers not electricians. Look up the work of Neil Muncy.
I remember years ago at a newspaper site that the clean Earth had plug and socket arrangement whereby the Earth pin had been rotated 90 degrees meaning only kit with the plug could use the clean earth arrangement. Stopped cleaners and maintenance personnel using thoses dedicated circuits for hoovers or worse still drills.
Yeah, I believe there are still variants on that theme, with T-shaped earth pins and so on. 😃
EMC is Electromagnetic compatibility, EMI is Electromagnetic Interference. Electromagnetic contamination is not a generally used term.
It is all noise generated by switch mode power supplies with poor to no screening.
Server Blade power supplies are extremely quiet, robustly made, virtually no EMC EMI at all. Radio Amateurs use them because they are noise free, so it can be done.
Agreed, I never heard the term EMC when talking about EMI. Maybe a UK thing though?
Hi, I hope you don't mind me wading in.
As a fully qualified Radio Amateur for many years, I have some issues with this clean Earth arrangement. Firstly, the conductors are laid side by side in the ducting, so there is little to no chance of stopping EMC interference, as it is radiated by the cables, which will actually enhance the pick up of interference by acting as a receiver line. I can see no improvement whatsoever, unless you use a common mode choke method.
Radio transmissions just travel between the gap, as if there was no gap, using capacitive and inductive coupling.
In long Audio cable runs, it has been a well known fact that you need to run a balanced twin coaxial cable with the outer screen grounded at one end only. This stops EMC getting in, as it appears 90 degrees out of phase at the Audio desk, so is eliminated (see common mode choke theory).
Secondly these are Voltage spikes not current spikes. You interchange these words far to frequently. Please replace the words current spikes with voltage spikes.
Interference spikes are Voltage in nature, and appear on the cables as such, no matter where the Line curvature is.
Further to, in a previous video eFIXX advocated using power line adapters for extending Wi-Fi, which introduces massive interference onto the power lines for many miles away from the property.
This clean Earth system simply cannot work to reduce or eliminate EMC Voltage Spikes or noise.
What am I missing.?
David G1ZQC Lincolnshire.
I'm curious about it from and EM side as well. Isolated Ground as it's known this side of the Atlantic, is used in IT mainly for ensuring that all equipment outlets are connected to a common point, primarily for a common ground reference which is important for serial signaling, RS232 & RS485 where the voltage is small enough a voltage differential of a few volts can interfere with the signal. Less of an issue now that Ethernet & Fiber are the primary means, and they could care less about a ground reference voltages.
There are not supposed to be any equipment generating interference connected to the clean earth sockets, only your well designed noise sensitive equipment.
@TheDrew2022: this is NOT an isolated ground. It's basically as if you fitted two separate electrical panels at your incoming meter and only connect sockets for "noisy" equipment to circuits on one of the panels. This means any current spikes in the noisy equipment will not generate induced current in the earth cable going to the sensitive equipment on the other panel.
I can’t understand in this day and age why things are designed to create all this hash and leakage . We are not in the best area for radio reception but some people can’t even listen to their radios due to all this hash , especially from some LED s plasma TVs etc.
In the old days the GPO would be on you like a ton of bricks if you had anything that produced any form of noise Interference etc.
@@andysims4906 It's not really a case of designed to, it's a case of not designed not to. So much of the stuff that comes out of that certain country these days has zero RFI/EMC etc filtering at all. Even when it does you'd probably want it removed as the capacitors etc that should be safety rated are usually just standard grade components and cheap rubbish at that.
What you need to realise is the Two CPCs are inside the same conduit, so will pick up the EMC noise right in situ.
It makes no difference if they run along side each other. RF radiation in the form of noisy Voltage spikes will bridge the gap like it is not there.
Look up RF thermocouple for the theory.
Clean Earths simply cannot work in the normal Physics world of RF.@@mrfrenzy.
Unfortunately I have come across sockets replaced on clean earth systems with standard sockets and the plastic pattress screws replaced with metal ones . In my many years of being a sparks ,Earthing arrangements are misunderstood or bodged or people don't believe and earth is important, we all seen earthing conductors missing or be cut off
Yur, ignorance can cause serious problems, hopefully some watching this video will learn from it. 😊
We don't have any clean earth arrangements at my place of work, but it's interesting nevertheless.. there's probably some very interesting physics going on with that link between the general earth and the clean earth at 3:01 because to me, that just looks like the general MET and the clean MET are essentially the same thing at that linked point. I'm presuming any noise generated on the general MET takes the easiest route to earth and therefore doesn't affect the clean MET? I'd appreciate a bit more information on that part.
And for anyone interested, the QR code means 'Internal>Level 02>2R13 Riser' , don't know why they don't just write that there instead of using a QR code though!
I thought the idea of having an MET and a clean MET bonded together at a single point further back towards the source was given way to more MESH bonded systems, like those described in BS EN 50310. For a local downstream example, in a comms room you would bond the distribution board for that room to the bonding earth bar that connects the I.T cabinets with dedicated bonds. You can also do this via a grid, however for most applications this is overkill.
You mention "IT Equipment" a lot in this video, but I've been in IT for 20+ years and have never once seen a Clean Earth anywhere amongst the equipment.
Question as we do these occasionally. Where running SWA's out to the feeder units would you
(A)run a 4 core instead of 3
(B) run a separate single earth and cable tie with existing swa and use single earth as clean earth or...
(C) use a 3 core swa, use the swa along with a bango/earthing nut as the dirty earth and the core within the swa as the clean earth.
We often run a cable out of the board to an earth bar and do the connections there, not really sure if this is the correct way, to me it all goes to the same place so unsure of the point.
Last point, sometimes we use the track to power wall sockets also. Whilst white plastic clean earth sockets are available, decorative metal sockets aren't, what do we do with the dirty earth? Connector block in back of box?
Hi mate thanks for the video. Clear as day, however I have a cabinet on site housing the clean earth bar as well as the safety earth bar and although the conductors going to these earth bars are physically separated, if I ring out the bars then I get continuity. The clean earth bar is raised on insulated points however the bolt within these insulated points is metal and it's used to mount the bar inside the panel.
Is this perhaps the area at which the 2 bars are allowed to be connected?
I've been to TUV Fareham a few times to get products through EMC testing. I think your viewers would very much appreciate a visit to that site if they'd allow it (and it's not too far away from you).
Beautiful outlet product but why are they still even bothering installing Strip Connector Terminals with screws to wire in the cabling? Rather use 221-2411 WAGO inline connectors with 3 Way Snap In Base Plate Holders. ..
Nice use of the QR code to ID the riser.
Yeah, it was a phenomenal installation.
Are clean earth sockets sometimes colored red? because the powertrack for clean earth is red, so i might just ask. Some manufacturers provide sockets in Yellow and Red in my area, I never really.know why buildings used them
Is this the same as TE/Technical Earth? Sounds a lot like the concept used in automation.
Is this system suitable for private homes or is it commercial use only?
It's probably a bit overkill for a typical home but it would work in theory.
Are you mining bitcoin at home ?
i have no idea about the electric wizardry (i'm a chemical technician) so i thought that this system is used for high end homes. Good to know you can use standard wiring. I'm saving Money so i can build an autarc home in the country side in croatia. A Family member repairs trams so he knows how to wire up stuff. My knowledge is limited to wiring Up LED 's and using wago 221's
Given the short cable runs and low number electrical items connected shouldn’t be a problem to identify what be the cause of emc? If for example were to install a high end home cinema then given its overall expense an extra cpc or two I doubt break the bank.
Clean earth systems can be usefull for electronics labs, music studios and even home hifi. Studios and Hifi usually use a clean earth as part of a (transformer) balanced power system and the earths are totally separate one clean earth for output and normal earth for the input these systems usually have an extra RCD on the output for safety (One on input side will not work) obviously the output is only for audio equipment and will have a non standard plug/socket arrangement. BTW EMC to an electronics enineer is ElectroMagnetic Compatability interference is EMI Electro Magnetic Interference
This might sound silly but could this not create a situation where there is a fault to an earth, the outer casing, which is only connected to the actual circuit via the main earth terminal and back again. That's an awfully long loop. If the socket run was connected with a tough cable rather than a metal connection could the whole thing run on one clean earth. Sorry but it's a long time since I've done commercial installs, 16th I think. 👴
A fault as in the line conductor to the general earth? 🤔
@@efixx Probably unlikely but a fault between the line conductor and the outer casing. Probably doesn't make any difference, just seems odd to have an earth path not going through the board supplying the circuit.
Since potentials are relative and not absolute, this sounds like an awful idea since noise in the ground are due to opposite currents in the power lines. Just perform proper filtering and don’t allow equipment manufacturers to induce currents in the equipment ground. Currents should return though the other line or neutral.