Electrician Jobs The old one still learning

[Gary latto]

Hi r2 end to end is 0.84

 

[mjroe]

With an r2 of 0.84 that would imply that the neutral reading you got was correct (0.84 / 1.66 = 0.5). So I'd be looking at a fault in the line conductor, most likely a loose connection in one of the accessories.

 

[Gary latto]

Hi mj thanks for reply .
Where does the 1.66 come from ?
Sorry if obvious and I'm just not getting it

 

[Gary latto]

Think the penny just dropped is it the 0.5 difference allowed between readings of end to end between phase and neutral end to end ?

 

[telectrix]

no...assuming the r1 is 0.5 ohms, you'd expext the r2 to be
1.67 X 0.5 (= 0.83) as the cpc is 1.5mm as opposed to 2.5mm. it's the rN that seems to be a bit high.

 

[Gary latto]

Hi telectrix I understand the cpc would be 1.67x greater due to only 1.5 , so yes like you say 0.5 x1.67 =0.83 .
But totally confused with regards the 1.66 calculation
So like you say the phase and cpc seem fine so neutral problem am I still looking at a bad connection do you think ?

 

[mjroe]

Ignore me, listen to Tel, I mis read your line and neutral end to end readings. The r1 seems to be right, as Tel said it's the rN that needs investigating, again a loose connection could quite easily be the cause.

The 1.66 (or 1.67 if you want to round up the recurring figure) comes from the difference in the cross sectional area of the live conductors and cpc. 2.5 (mm2) / 1.5 (mm2) = 1.666666666 (recurring).

So r2 should be 1.66 x greater than r1 (and rN).

Hope that makes sense.

 

[telectrix]

yep.might just be a terminal screw a bit loose in a socket. any why the confusion with 1.66? it's the ratio of 1.5/2.5.

 

[telectrix]

Ignore me, listen to Tel, I mis read your line and neutral end to end readings. The r1 seems to be right, as Tel said it's the rN that needs investigating, again a loose connection could quite easily be the cause.

The 1.66 (or 1.67 if you want to round up the recurring figure) comes from the difference in the cross sectional area of the live conductors and cpc. 2.5 (mm2) / 1.5 (mm2) = 1.666666666 (recurring).

So r2 should be 1.66 x greater than r1 (and rN).

Hope that makes sense.

you are excused due to the fact that you are in Devon. too much time smuggling booze and hanging pirates.

 

[mjroe]

smuggling booze

As I was born in Somerset it really aught to be scrumpy...

 

[telectrix]

my favorite tipple at my old local was Addlestones cloudy cider on draft. 7%. only 2 of us drank it, but we got through 2 x 10 gallons a week between us. sadly my mate has moved to a better world, having been crushed between a 50ft. canal barge and a lock when pi$$ed.

 

[Gary latto]

Confused with the 1.66 cause I learnt the 1.67 factor
Guys many thanks for your replies/answers all makes sense now thanks yet again much appreciated to all

 

[telectrix]

yeah, it's that tricky maths again. 1.6666666666 rounded up to 1 67. was much easier when we had roman numerals. XVIIIIIIIIIIIIIVIII.

 

[static zap]

yeah, it's that tricky maths again. 1.6666666666 rounded up to 1 67. was much easier when we had roman numerals. XVIIIIIIIIIIIIIVIII.

I always preferred vulgar fractions 2.5/1.5===5/3

(then reminding your common sense 0.99999999 .. =1)
so a third is 0.333333333 ..

 

[Pete999]

I always preferred vulgar fractions 2.5/1.5===5/3

(then reminding your common sense 0.99999999 .. =1)
so a third is 0.333333333 ..

Wonderful