PCB ground planes

[Newmarket]

I have seen "bootleg ground" wiring advice for some appliance hook up instructions (my house wiring does not include a dedicated safety ground wire.) Tying a chassis ground to neutral "should" be safe as long as the 0V neutral path is solid. If that neutral connection opens up, the chassis could be energized by leakage from the line connection.

JR

Would it not be preferable to implement a PEC in your domestic wiring ? I might be misunderstanding the situation from the UK where a PEC is assumed. Whether it is tied to Neutral wherever or literally driven into the Ground. Depending on what the distribution authority/ provider provides (or not) at a given location.

 

[Mr. Moscode]

I believe that prior to joining the EU and the wish to harmonise mains voltage across the EU the quoted 'tolerance' HAD been + - 10% but by a bit of wrangling it was changed to plus 10 and minus 6 % on a new nominal 230 Volts where the majority of european countries had aimed with others being 220 and the UK 240.
Having wrestled with a fair few 'American' designed (Mexico assembled) 'industrial' power supply units they do allow ripple when fed from 50Hz mains at 208 Volts when on the 230 Volt setting which is fair enough. I suspect using ithem in USA or Japan would allow slightly greater leeway due to increased frequency. Of course transformer manufacturers design and make power transformers with the intention that will meet (or exceed by a suitable margin) the requirements for international safety approvals because getting it 'right first time' is a lot better than the fallout from faulty product.
As an observation, the number of USA sourced mains transformers that 'buzz' mechanically when powered with 50Hz is rather disappointing.

Iron poor xfmers diet. They need Geritol.

 

[JohnRoberts]

Would it not be preferable to implement a PEC in your domestic wiring ? I might be misunderstanding the situation from the UK where a PEC is assumed. Whether it is tied to Neutral wherever or literally driven into the Ground. Depending on what the distribution authority/ provider provides (or not) at a given location.

I searched "PEC" and found Phillipines electrical code, and something related the Perdenales (?) TX, then there's

PEC (cable system) or Pan European Crossing, a European fibre optic network. Perfect electric conductor. Peripheral Event Controller, an implementation of autonomous peripheral operations in microcontrollers. Perivascular epithelioid cell tumour (PEC tumour) Planetary Exploration of China,

There was one youtube video but i just say no to them...

Please explain what you mean in simple english.

JR

 

[abbey road d enfer]

Protective Earth Conductor?

 

[abbey road d enfer]

I'm just curious why it seems that risks of wrong cabling are more frequent in the US than in Europe.
I believe I have never seen a socket wired wrong in my life.
Is it because of bootleg grounds, which are unknown here (but exist in some parts of Scandinavia)?
Is it possibly the different location of GFCI's? In Europe, GFCI's are at the distro panel, never in the sockets. It's almost impossible to attach a PE wire to Phase or Neutral in the distro panel, since Earth is on a separate terminal.
Unless the sparky is daltonian, there's no possibility for mistake.

 

[Tubetec]

Back in the old days power transformers usually had a single chamber bobbin ,
now its almost always the case that a power transformer has a dual chamber , so primary and secondary are not wound one on top of the other . Side by side windings might have more noise where in the layered approach a center tapped LT winding might be used to help better screen between primary and HT windings . Safety probably takes precedence in these times .

Toroids are popular these days but you typically only have tape insulation between primary and secondary and wires on the same winding with vastly differing potentials cross over , thats very often the weak point you find in broken toroids .

 

[Brian Roth]

I'm just curious why it seems that risks of wrong cabling are more frequent in the US than in Europe.
I believe I have never seen a socket wired wrong in my life.
Is it because of bootleg grounds, which are unknown here (but exist in some parts of Scandinavia)?
Is it possibly the different location of GFCI's? In Europe, GFCI's are at the distro panel, never in the sockets. It's almost impossible to attach a PE wire to Phase or Neutral in the distro panel, since Earth is on a separate terminal.
Unless the sparky is daltonian, there's no possibility for mistake.

In the USA, GFCIs are NOW required for kitchen and bathroom outlets where water might be located. No other circuits require "guffers" (as an old electrician friend called them with his thick southern USA accent).

Hence, all new wiring here in the USA (that is not in a kitchen, bathroom, laundry room) is fed from a circuit breaker on the "hot" 120 VAC side and a grounded neutral. No GFCI required otherwise. Kind of an accident looking to happen, eh?

Older houses like my Mom's (and John Roberts') only have two wires to each receptacle. Hot 120 and (grounded) neutral. The receptacles have only two slots.

My previous house was built in 1970. Then, all receptacles had to be three prong (added safety ground). FWIW, while I was doing room by room remodeling, I replaced all of the 40 year old 3-wire receptacles. I discovered that maybe 25% had hot and neutral wires flipped since the day the house was built! I guess the "sparky" in charge had his stoner 16 year old cousin doing the outlet wiring.

Hell...in several cases, the moron even had the "wire wrap" around the receptacle screw going counter-clockwise.

Bri

 

[Newmarket]

I searched "PEC" and found Phillipines electrical code, and something related the Perdenales (?) TX, then there's


There was one youtube video but i just say no to them...

Please explain what you mean in simple english.

JR

Protective Earth Conductor. Although I believe that in USA it's usually just termed "PE". And in UK it's often "Circuit Protective Conductor" (CPC).
PEC can also refer to "Perfect Electrical Conductor" so maybe best avoided although its meaning is clear wrt electric installation wiring.
Anyway, question was basically whether it's practicable to implement three conductor wiring in your system

 

[JohnRoberts]

Protective Earth Conductor. Although I believe that in USA it's usually just termed "PE". And in UK it's often "Circuit Protective Conductor" (CPC).
PEC can also refer to "Perfect Electrical Conductor" so maybe be avoided although its meaning is clear wrt electric installation wiring.
Anyway, question was basically whether it's practicable to implement three conductor wiring in your system

In the US that is called EGC (equipment grounding conductor). As I already shared my house is wired without EGC.

I have installed GFCI outlets in the rooms with plumbing (kitchen, bathroom, and laundry room). I added a real EGC to ground my hot water heater to the fuse box with a separate wire, I also grounded the outlets next to my washing machine and kitchen sink.

Rewiring my entire house is not a practical consideration.

[edit- today my search finds PE and PEN (a combined earth/neutral connection). /edit]

JR

 

[Mr. Moscode]

Speaking of GFCIs, I was in Home Despot yesterday looking for a gfci breaker but all I found were gfci breakers with arc protection, unless I missed a few. The prices were in the $60-70 range for 1, Yikes. We have an arc protect gfci in our house which keeps tripping when we use a vacuum cleaner with a brush motor. It is a pita.

GFCI outlets are much cheaper and they can protect a string of outlets.

I noticed they have 2 wire replacement line cords, too.

I don't know how we survived the house wiring of yesteryear. By today's standards we should all have been electrocuted, (except this group - we were born with double insulation).

 

[Newmarket]

In the US that is called EGC (equipment grounding conductor). As I already shared my house is wired without EGC.

I have installed GFCI outlets in the rooms with plumbing (kitchen, bathroom, and laundry room). I added a real EGC to ground my hot water heater to the fuse box with a separate wire, I also grounded the outlets next to my washing machine and kitchen sink.

Rewiring my entire house is not a practical consideration.

[edit- today my search finds PE and PEN (a combined earth/neutral connection). /edit]

JR

Okay. Trans-Continental Terminology can be difficult and it changes locally - I think here (UK) we are upto IEC version 18 for wiring standards . I may have a unhealthy tendency to watch too many Sparks' (electricians) YouTube channels !
House wiring understood. It's simply not a thing here to have unearthed sockets if you want a good EICR (report on your electrics) and if the electricity distribution authority sees it the electricity would be disconnected.
fwiw I once gave the okay for a tenant to wire for an electric cooker (the existing was on gas) on the basis that he worked for his father installing commercial air con'. This was before "Part P" came into force in the UK. Big mistake, Meter Reader visited, saw the wiring. Condemned and disconnected !

 

[abbey road d enfer]

Okay. Trans-Continental Terminology can be difficult

+1

fwiw I once gave the okay for a tenant to wire for an electric cooker

cooker (UK)<=>range (US) ?????

 

[Newmarket]

+1

cooker (UK)<=>range (US) ?????

I guess. Here a "Range" probably refers more to an AGA type cast iron thing rather than our own modest oven/grill/hob combo.
AGA Range Cookers - World's Best Cooking Experience | AGA Living

 

[FIX]

That doesn't make it correct.

Our new political system justifies everything. All you have to do is say it and it's true. That must apply to grounding too...

 

[abbey road d enfer]

Our new political system justifies everything. All you have to do is say it and it's true. That must apply to grounding too...

What was I thinking? Thanks for reminding me.

 

[Cqwet Dbdfte]

I recently designed a tube moving coil preamp PCB, and I used solid ground pours (not "hatched"), top and bottom. To budget effect I used 2-layer, but 4-layer would have included heater traces, now twisted wires. Throwing caution to the wind I also used a cheap SMPS, which had some not-so-nice high frequency artifacts needed to be sorted out with uH and nF filters.
As the tubes are VHF pentodes and triodes, capacitive loading would be a bonus, and a max 47K input would not be much upset by a couple of pF board traces. Even a MM would need some pF. MC transformer stepped up use ~ 22K load.
The board is attached to an aluminum plate, with many threaded AL standoffs to grounded PCB vias, and the plate is attached with a single screw to the outer case. That plate provides a heatsink for conduction cooling fullpak-TO220 HV MOSFETs. Ground loops has not been an issue. RIAA filter shaves off gain 40dB from 20Hz to 20KHz anyway, and continues way beyond that, so HF roll-off here is a bonus. I'm not looking for MHz performance.
Vintage electronics typically use "star ground", or a "bus wire", as ground planes were not an option in the point-to-point wiring era.
I'm planning to use a 1-sided aluminum PCB for an all SMT design, as it provides a heat sink for my constant current plate loads.
Via sizes, and ground-pour distance to traces can be well specified, controlling capacitive loading a little. Using 1.6mm thick PCB reduces capacitive load, compared to 4-layer where I typically would use a 0.2mm or 0.1mm thick dielectric in RF circuits.
Yes, all solid ground planes worked OK for a tube preamp.

 

[abbey road d enfer]

Yes, all solid ground planes worked OK for a tube preamp.

Indeed.
In most tube projects, the typical impedance of circuits make the "ground" traces resistance unconsequential, as long as heater and rectifier currents are kept thoroughly separate from the rest.

 

[Philbo King]

Totally, I am using an old version of Eagle and I am finding I always have to modify the stock library footprints increasing pad sizes. This goes for the smaller through hole components as well.


I am keeping the psu on a separate board, so that should avoid psu ground currents affecting audio grounds.

I have read about the treble loss problem, yet I am seeing many commercial and diy products using ground planes. From the research I have done I couldn't find clear answers about this subject.

It's pretty common to split ground planes as needed to direct ground currents to avoid problems like this. I've seen it (and done it) in RF/microwave and mixed digital/analog boards.

 

[Cqwet Dbdfte]

Yep, separating ground planes is very common in mixed signal and very sensitive ADC jobs, digital ground, analog ground, etc, then combined at some single point. In RF mostly everything is hard grounded (and shielded) everywhere.

 

[Mr. Moscode]

Looks like you did everything right. Well done!

Passive or active RiAA? How does it sound?