GR Research B24 AC Cord Review

[BlackTalon]

There is a long story about Codes and industry standards: typically they are updated on a 3 year cycle. The currently adopted codes may have been published 2 years ago and the adopted by reference industry standards may be 3 years older than that. Remember that the codes are a minimum standard. Then a building designed 5 years ago may permitted under codes and standards 5 or 10 years old. Just because there is a new published code or standard does not mean that we use it.
...

I neglected to mention, that I use the old ASHRAE hand books under my computer monitor to prop it up off my desk.

(this is for the US)

Yep for the IBC codes. The Ashrae handbook has 4 volumes and one gets updated each year according to their web site. We don't deal with Ashrae much, but live in the OBC codes and UFCs.

And we keep the old code books around so we know what the requirements were when a building or building system was constructed/ installed.

Code adoption is another matter, as it's up to local jurisdictions. DC only switched form the 2012 IBC codes this past year. Some other places in the region were still on 2012 or 2015 in 2021. Many have not updated to 2018. And of course the IBC codes are not real codes, they are only models -- the jurisdictions make them real by indicating they must be followed, usually with the jurisdiction's unique set of additional requirements.

 

[Lambda]

However the measured data are a fact insofar as the induced noise is 110 dB below the signal peak.

sure but this is only true for the used signal level.
if a stronger signal would be used it would be more then 110dB and vice versa.

You can also say it the other way around "the signal is 110dB above the induced noise"
But this tells us noting about the noise amplitude.

the induced noise is 110 dB below 2V, if it was 20 V the induced noise is 110 dB below 20V. The relation is as it is.

Sure but 110dB below 20V is still 10x more then 110dB below 2V
So if this is supposed to show the noise level its not doing so

Now if lets say the peak level was 20V the induced noise is 110 dB below 20V. If one now remeasures with a lower peak level of 2V the induced noise would be 90 dB below 2V (same as 110 dB below 20V, because its independent of the signal level). Hence using a lower peak level outside of this test scenario would in fact lead to a lower peak/noise ration

Exactly.
By choosing signal level you can arbitrary influence the SNR ratio you get as result.
(in real life within limits of what the instrument is capable)

So saying SNR is n dB is meaningless without saying at what amplitude.

In real life though this cable is fed with a rather very high "signal" of 120V which is about 15 dB higher than the APX can deliver (20V?). This raises the relation of peak to noise by ~ 15 dB. If the measurement had been done with a peak level of 2V a 120V "signal" would lead to an rise of 35 dB. In both cases the noise is utterly inaudible.

This is also not my point
In real life we don't listen to mains and don't use power cable as interconnect*.
in real life the signal would be 120V or 240V
My point was only that the testing is methodically flawed in the way taht.
1. We can't see the Absolute noise level from this test we can only see a Signal to Noise Ratio
2. And this resulting SNR can be anything Amir want's (within limits of what the instrument is capable)

In real life this is pointless test. because its a stupid power cable.
He could have said measured / shown / said:
The fancy cable has has x dB more (or less) inductive noise pickup/emission

or better a noise rejection vs. frequency measurement to compare the cables.
like this:

*btw. How was the cable used as interconnect?
Balanced or as single ended?
With what input and output impedance?

 

[amirm]

The cable on my Tripp-Lite power bar is not UL marked either.

You are being misleading with that statement. The whole thing is UL certified. Here are the specs from their website: https://www.tripplite.com/1u-rack-m...ight-angled-widely-spaced-15-ft-cord~RS1215RA

There is no requirement that the cable itself carry such a mark. I can't believe you are trying to make a case that power cords are sold without safety certification. Here is a random/quick search on Amazon for a cheap power strip:

It is even in the darn heading of the product.

 

[Blumlein 88]

Take a look at this plug end, which you can buy in any hardware store along with the other end of it. UL listed. If you buy these and connect 3 wires between them does it make this a UL-listed power cord?

You can call it UL recognized if you use a UL listed cable and make it yourself. It still isn't a UL listed cable without a 3rd party certifying it.

 

[DualTriode]

Take a look at this plug end, which you can buy in any hardware store along with the other end of it. UL listed. If you buy these and connect 3 wires between them does it make this a UL-listed power cord?

View attachment 218932
You can call it UL recognized if you use a UL listed cable and make it yourself. It still isn't a UL listed cable without a 3rd party certifying it.

No, it is a contraption made with UL listed parts.

I once worked at a large teaching hospital campus where the Plant Operation Department bought a direct fired heater for a paint spray booth. The Fire Marshall pointed out that the heater had UL Listed parts, However the heater was not listed. The PO&M Department Manager was Pissed that he had to buy and install a new UL Listed heater.

 

[amirm]

Take a look at this plug end, which you can buy in any hardware store along with the other end of it. UL listed. If you buy these and connect 3 wires between them does it make this a UL-listed power cord?

No, the whole assembly needs to comply with UL817. There are a ton of requirements from pull strength to temperature rise, dielectric voltage testing, insulation resistance, aging tests, crush test, drop test, short-circuit, etc. Use of a UL listed plug gets you the comfort of knowing that aspect of UL 817 is covered. But the rest still requires testing and conformance.

 

[Blumlein 88]

No, it is a contraption made with UL listed parts.

I once worked at a large teaching hospital campus where the Plant Operation Department bought a direct fired heater for a paint spray booth. The Fire Marshall pointed out that the heater had UL Listed parts, However the heater was not listed. The PO&M Department Manager was Pissed that he had to buy and install a new UL Listed heater.

That was exactly my point. And there is a category called UL recognized. It is when all UL listed parts are used, but the complete component has not been certified by a 3rd approved testing outfit. That step is needed to get UL listed.

A gross example of incompetence would be using UL listed 20 amp cord ends, and a 10 amp UL listed cord and someone thinking the whole thing is UL listed and suitable for loads up to 20 amps. That situation is why the Fire Marshall wanted a UL listed complete device. Here is a chart and before knowing this I used to wonder what the backwards RU mark was supposed to mean.

c3controls

c3controls - the best electrical controls business on the planet!

www.c3controls.com

 

[DualTriode]

That was exactly my point. And there is a category called UL recognized. It is when all UL listed parts are used, but the complete component has not been certified by a 3rd approved testing outfit. That step is needed to get UL listed.

A gross example of incompetence would be using UL listed 20 amp cord ends, and a 10 amp UL listed cord and someone thinking the whole thing is UL listed and suitable for loads up to 20 amps. That situation is why the Fire Marshall wanted a UL listed complete device. Here is a chart and before knowing this I used to wonder what the backwards RU marked was supposed to mean.

c3controls

c3controls - the best electrical controls business on the planet!

www.c3controls.com

Then along comes the building inspector with the National Electric Code (NFPA70) in hand and red tags that "power strip" because extension cords are not allowed under you desk UL listed or not. The receptacle in the wall is sized for only 180 Watts.

National Fire Codes (NFPA) trumps UL.

 

[voodooless]

Would be nice to have an overview article of various regulations and marks.

 

[Blumlein 88]

Then along comes the building inspector with the National Electric Code (NFPA70) in hand and red tags that "power strip" because extension cords are not allowed under you desk UL listed or not. The receptacle in the wall is sized for only 180 Watts.

National Fire Codes (NFPA) trumps UL.

Did you mean 1800 watts? Typical 15 amp/ 120 volt receptacle.

 

[DualTriode]

Did you mean 1800 watts? Typical 15 amp/ 120 volt receptacle.

No, No, not 1800 Watts, that is the branch circuit. At 1800 watts there could be receptacles behind 10 desks. If all the receptacles have a power strip the branch circuit could be way over loaded.

 

[Blumlein 88]

No, No, not 1800 Watts, that is the branch circuit. At 1800 watts there could be receptacles behind 10 desks. If all the receptacles have a power strip the branch circuit could be way over loaded.

Well that is why they made breakers, GFCI, and AFCI devices, plus they sometimes even fuse the stuff we plug in.

 

[Paco De Lucia]

To be honest I believe that Amir has been testing things like power cables to pretty much show how absurd it is to treat items such as this as critical in the audio chain. He arbitrarily chose some tests for noise etc knowing that it doesn't really matter. Now everyone is jumping on the subject as if its a subject. Audio science people can argue the leg off a donkey in most normal circumstances. The trouble we have here is that the donkey was already a quadruple amputee before Amir met the poor fella. Good morning.

 

[Blumlein 88]

So this explains the 180 watts. Different in commercial vs residential and I was thinking residential. Also, every office I've been in violates that 180 watts per outlet.

How Many Receptacle Outlets Can You Install on One Circuit?

We can install an unlimited number of outlets on one circuit when talking about a 15-amp 120-volt convenience outlet branch circuit in a dwelling.

www.jadelearning.com

 

[voodooless]

Now everyone is jumping on the subject as if its a subject.

Who is? I've seen nobody do this?

 

[DualTriode]

So this explains the 180 watts. Different in commercial vs residential and I was thinking residential. Also, every office I've been in violates that 180 watts per outlet.

How Many Receptacle Outlets Can You Install on One Circuit?

We can install an unlimited number of outlets on one circuit when talking about a 15-amp 120-volt convenience outlet branch circuit in a dwelling.

www.jadelearning.com

I am a facilities commercial person, that is where my head goes first.

If your commercial building burns down and the source of the fire is traced back to a overloaded circuit the Insurance company may not pay. Circuit breakers can and do fail closed.

Residential or commercial the circuit breakers are designed for faults. The code only allows for loading to 80% ampacity. If your circuit breakers are tripping due to connected load not fault you are not code compliant.

 

[Blumlein 88]

I am a facilities commercial person, that is where my head goes first.

If your commercial building burns down and the source of the fire is traced back to a overloaded circuit the Insurance company may not pay. Circuit breakers can and do fail closed.

Residential or commercial the circuit breakers are designed for faults. The code only allows for loading to 80% ampacity. If your circuit breakers are tripping due to connected load not fault you are not code compliant.

One of the places I was employed (not as an electrician) the chief electrician didn't trust breakers. Fuses only for his personal home. On the job he wanted to replace them every 5 years, but management only agreed to a ten year cycle.

 

[delta76]

Stump upon this Youtube comment. Pure gold.

 

[LTig]

YMMD

 

[Spkrdctr]

As I pointed out earlier, a technically sound argument for why some power cords could make a difference under certain conditions can actually be made. So clearly the case is more complex than "power cords don't matter at all, ever" vs "power cords make a huge difference".
Tom

Can you explain this? Any testing you know of to back it up? Is it only with exotic poor performing equipment? Does it involve any normal regular mainstream, not boutique products? Thanks for any info.