Zs

[martysparky]

Maximum loop impedance for type B 40A breaker?

 

[DurhamSparky]

1.15 ohms...

 

[Guest123]

1.20 ohms....!!! thats from onsite guide so has 20% knocked off...!!

But a 40A type B is 1.15 ohms at 100% value.......

 

[DurhamSparky]

lenny 1 - 0 steve lol

 

[martysparky]

I was just looking at a multiple choice paper and the options are

A. 11.5
B. 0.11
C. 115
D. 1.15

I looked at the OSG page 103 and it gives 0.93

 

[Guest123]

The osg values are temperature corrected at 80%

BS 7671 value = 1.15ohms x 80% = 0.92ohms

 

[martysparky]

But a 40A type B is 1.15 ohms at 100% value.......

could you tell me what page that is in BRB please

 

[Guest123]

P49.

 

[DurhamSparky]

page 49

 

[Guest123]

lenny 1 - 0 steve lol

lololol.

 

[martysparky]

cheers guys was flipping pages last half hour


Whats more annoying is I have a tab on the page marked Zs. lol

 

[DurhamSparky]

dont thank me...!! i will burn a house down....lol... no idea where i got that from...! oh well lol

 

[Guest123]

Getting too excited again Steve......

 

[DurhamSparky]

for some reason 1.20 flew in to my mind...!! dunno , i will fathom out from where it comes from shorty, i must have used it some where in my calc recently..!! lol

but thats what the OSG and Easy Cert are for!!! stop me thinking and number generating!!!

 

[Guest123]

1.20 was the old max Zs for a 40A type B in the 16th ed when the calcs were based on 240V as opposed to 230V now.