What should it be called?

[EFLImpudence]

fair enough. To have stuck with 'carriage' would probably have been reasonable - but "horseless" would be a bit silly in 21st (or second half of 20th) century, wouldn't it?

Yes, of course it would, but it is still correct.
Calling it a boat because they don't have horses either would have been silly.

If they are genuinely 'new' names, then that might be reasonable. What I find unfortunate is when the so-called 'new name' is a name which always has had (and continues to have) a totally different meaning (e.g. lamp).

I am not sure of the origin.
Perhaps Edison thought his new invention looked like an oil lamp and it has been corrupted the other way round.

If the magnitude of the resistance is measured, it's a resistance measurement, not a continuity test.

Yes, but it confirms the continuity as well.

Yes, but if the actual resistance is being measured (rather than Yes/No for above/below some specified measurement) then it is a resistance measurement, not either of those other two things.

That we can do two things at the same time does not alter the result.

I have a 'continuity tester' in my toolbox. It has an LED and a buzzer, but no other display of any sort. I also have meters that can measure resistance.

So, it is correct, then.
Would adding an ohmeter alter the buzzer?

 

[PBC_1966]

I have a 'continuity tester' in my toolbox. It has an LED and a buzzer, but no other display of any sort. I also have meters that can measure resistance. They are different things.

They certainly are, although many simple continuity testers often have a small range between indicating "full" continuity and no indication for "open," in which subtle changes in the sound can give an approximate indication of resistance. It's often a case of anything below a few tens of ohms giving "full" continuity and anything over a couple of hundred ohms showing as "open," although obviously subject to much variation from one device to another.

Somewhere in my boxes I have the "old faithful" Hosiden-Besson "Bleep-Test" I grew up with as a kid - The one in the green casing with pocket clip on the back. I'm sure you either know it or would recognize it. It's been so long since I've used it that I can't remember the sort of resistance values concerned, but there's certainly a distinctive point as resistance increases at which very clear "bleep" becomes more of a weak "squeak" before disappearing altogether.

 

[ericmark]

Continuity test I see as belling out. i.e. you test there is a circuit but don't measure any resistance.
The rail system does seem to have a lot of name miss use. Rail car we call a tram i.e. single unit.
Train must have more than one unit.
Engine is the tractive unit.
Push pull is a special carriage and engine allowing the driver to control the train from the carriage. (fireman remains in the engine.)

The same should work with electrical systems. The words should describe the item. I wire supported at intervals along it's length is a festoon. This includes the wire inside a glass tube what is heated to give out light. The festoon tube. Although the fluorescent tube is same shape it's not a festoon as there is not support for the filament inside the tube.

MR16 stands to multifaceted reflector 16/8 inch diameter never really works out why 16/8 inch rather than 2 inch expect it's connected to 4/3rds we get with cameras? Seems related to cathode ray tubes. However using LED then often no multifaceted reflector so they would just be a 16 lamp! Why when both the GU5.3 and GU10 were both MR16 we see MR16 linked to the GU5.3 and not so much to the GU10 I don't know.

Guide lines and regulations also seem to lend their names to products. The L2 GU10 is so called and the dimple and spike stop combination heat and light units being fitted in holders called L2 GU10 to allow them to comply with Part L2 building regulations. General guidance note 38 says how test leads should be made to use with low voltage so we call then GN38 leads.

With a three voltage stepped square wave, positive, zero and negative rather than jumping direct from positive to negative they call it a simulated sine wave. How? It's not a wave form and it is clearly not sinusoidal. Next the will call a salute and simulated wave!

 

[JohnW2]

If the magnitude of the resistance is measured, it's a resistance measurement, not a continuity test.

Yes, but it confirms the continuity as well. ... That we can do two things at the same time does not alter the result.

Provided one has a definition of 'continuity', an ohmeter can, indeed, do both things - but that doesn't make the two things the same. What "test" we are doing depends upon what sort of result we are interested in, and are going to record. If our interest is only in knowing whether or not the resistance is below, say, 10Ω, and we are going to record the result as Yes/No, or <10Ω/≥10Ω, then we are undertaking a continuity test. If we are interested in, and are going to record, the actual measured resistance, then we are undertaking a resistance measurement.

The sample "Schedule of Test Results" for final circuits in BS7671 has a column headed "Continuity", but I don't really think it would be happy with Yes/No entries, or <10Ω/≥10Ω ones, do you?

Kind Regards, John

 

[ericmark]

In 2000 I was given a job to get the records of a company up to date. Both in-service equipment and installation. The latter resulted in new equipment, the former there was a to date unused PAT tester all it required was a calibration certificate. It was duly sent via our local whole sale outlet for calibration. I asked if we could have computer software to record the readings and this was also purchased.

However the old "PAT" tester (hate that phrase as the T is PAT stands for tester) had simple go/ no go lights and the software required a ohm reading. Complained to software manufacturer and answer was so easy. Enter the limits giving on the calibration certificate. However reading the traceable document it did not have the readings on it. However I was assured it was only a case of asking the testing house for a replacement with the readings on the document. It was after all a traceable record.

In the mean time the software was returned and I used Excel and where I wanted the ohm reading I used words like cohm and iohm so latter I could used replace command and update all the records with the actual pass value. Because dealing via local whole sale outlet not direct weeks dragged on near completed all the required testing and still no replacement certificate. So it got down to threat level no certificate then no more custom. At this it was requested we return the PAT tester as the testing house could not find the traceable records. This was done.

Week latter we got the report that the tester had been produced on an earlier edition of the wiring regulations and it was not possible to re-calibrate to today's standards. All my records were rubbish. OK there would not be any dangerous equipment even old standards insured that, but that put me right off using calibration houses and using testers which are simple go/no go results.

It has not changed. The EZ150 Martindale plug in tester is a good example. It has go/no go lights for loop impedance. There are 8 lights in all (4 with two colours), but the best reading is better than 1.50Ω which was years ago the pass mark for a ring final using a 30 amp fuse. Today however the value is lower than that so better than nothing like that old PAT tester, but clearly outdated.

As a result of this I don't like the pass/fail entry. I want to know why something has failed. Has the distribution failed because it does not have the right BS EN number stamped on it? Because it contains asbestos? Because it has a plastic lid? Because it has blanks which can be removed without a tool? What ever the reason I want to know the reason not has a simple fail. There may be a replacement for a plastic lid which does not require a new unit, or a metal box which can be used to surround it.

Some items yes. Polarity with OK in the box great. Ring final continuity however is hard as you have three measurements each which may be different. And this also depends on method the removing cables from consumer unit and linking for test will test line and neutral together. It will also highlight spurs and figure of 8. However unless one records the readings what is the point? You would need every socket to be listed with results.

 

[JohnW2]

that put me right off using .... testers which are simple go/no go results. Some items yes. Polarity with OK in the box great. Ring final continuity however is hard as you have three measurements each which may be different. And this also depends on method the removing cables from consumer unit and linking for test will test line and neutral together. It will also highlight spurs and figure of 8. However unless one records the readings what is the point?

In many situations, certainly including the testing of a ring final, one needs to know, and record, actual resistance measurements. My only point, which many probably regard as pedantic, is that if one is doing that it should be called "resistance measurement", not "continuity testing".

Kind Regards, John

 

[EFLImpudence]

My only point, which many probably regard as pedantic,

A bit.

is that if one is doing that it should be called "resistance measurement", not "continuity testing".

On the schedule of test results on page 434, the headings are:

Ring final continuity (Ω)
with r1, rn, r2 above the columns

and

Continuity (Ω) (R1+R2) or R2
with (R1+R2), R2 above the columns.

(I don't know why the illogical difference in format but that seems to be what we have become used to in 7671)

So we measure the resistance to prove continuity.

I don't think that is too unreasonable - especially as we recently discovered/realised that some continuity testers beep at a very high resistance (I can't remember the figure).

 

[JohnW2]

On the schedule of test results on page 434, the headings are:
Ring final continuity (Ω), with r1, rn, r2 above the columns
and
Continuity (Ω) (R1+R2) or R2, with (R1+R2), R2 above the columns.

Quite - and, strictly speaking, that is incorrect. "Continuity" is not measured in Ohms

So we measure the resistance to prove continuity.

We do - and that's perfectly reasonable, given that 'continuity' is defined (albeit arbitrarily) in terms of resistance. However, if one's interest goes beyond knowing whether the resistance is above or below some threshold (and if one is going to record the actual measured resistance), then, strictly speaking, what one is doing (hence what one calls what one is doing) goes beyond 'continuity'.

I don't think that is too unreasonable - especially as we recently discovered/ realised that some continuity testers beep at a very high resistance (I can't remember the figure).

I don't think that anyone (certainly not I) has suggested that one should use a 'continuity tester' (whatever it's beep threshold), and hence undertake 'continuity testing', as the means of testing, say, a ring final. As I recently wrote to eric, one wants, needs, and needs to record, actual resistance measurements in order to properly test most circuits, certainly a ring final. Apart from anything else, one obviously has to apply a whole range of differing 'acceptance thresholds' in different situations.

Yes, it's pretty pedantic, and not the cause of any confusion or ambiguity. However, to call a resistance measurement a 'continuity test' is no less 'incorrect' than are many of the misuses of terminology/vocabulary which you have said (not unreasonably) that you feel should be 'corrected' when they are used. If it were just a question of "electrician's jargon", that would probably be fair enough - every trade and profession has it's own jargon, used only by the "in crowd". However, this goes further than that, since everything from BS7671 and GN3 downwards appears to have adopted this incorrect use of "continuity testing".

Kind Regards, John

 

[stillp]

Continuity means the existence of a path of sufficiently low impedance to fulfill its function, so I don't see how you can verify continuity without measuring resistance, or how you could define continuity without specifying a maximum resistance/impedance.

 

[PBC_1966]

Continuity means the existence of a path of sufficiently low impedance to fulfill its function, so I don't see how you can verify continuity without measuring resistance, or how you could define continuity without specifying a maximum resistance/impedance.

Two contrasting examples: Verifying suitable (i.e. sufficiently low resistance) continuity for the earth conductor on a 100 ft. long branch circuit in a house vs. verifying continuity on a 5-mile long telephone line.

 

[JohnW2]

Continuity means the existence of a path of sufficiently low impedance to fulfill its function, so I don't see how you can verify continuity without measuring resistance, or how you could define continuity without specifying a maximum resistance/impedance.

As I've said, one can't - one can only undertake a 'continuity test' in the context of a definition of the ('Yes/No') threshold relevant to the situation in question. That's why it is, IMO, daft to talk about this as 'continuity testing', since one would have to have a different definition of 'continuity' for each situation.

We've both said that what is required is a quantitative resistance measurement, so that one can determine whether it is sufficiently low for the situation in question.

Kind Regards, John

 

[ericmark]

Continuity means the existence of a path of sufficiently low impedance to fulfill its function, so I don't see how you can verify continuity without measuring resistance, or how you could define continuity without specifying a maximum resistance/impedance.

Two contrasting examples: Verifying suitable (i.e. sufficiently low resistance) continuity for the earth conductor on a 100 ft. long branch circuit in a house vs. verifying continuity on a 5-mile long telephone line.

Good point if the telephone works you have continuity which can be shown without measuring the impedance. The same using a RCD tester the earth continuity is confirmed because x mA can flow it does not measure the impedance.

 

[ban-all-sheds]

Other than the name of a TV program like "Very last of the summer wine." last is the last, end is the end not point trying to qualify further.

And for how many years have you been seeing newspapers and magazines publishing the "ultimate" Christmas gift/cooking/entertaining/holiday/get-a-*)£"^$^(ing-dictionary guides?

They lie, over and over again, year after year.

 

[ericmark]

So the reply I will tell lies all lies and nothing but lies got the answer that is very honest of you?