Earthing for an EV Charging Point

[uksparks]

Im is the max neutral current, so having just worked it out,i think its worked out at 91A, does this figure sound like a realistic figure? I don't really know what to expect here...

 

[spark 68]

Don't forget to add your new charger load

 

[Simonslimline]

Im is the max neutral current, so having just worked it out,i think its worked out at 91A, does this figure sound like a realistic figure? I don't really know what to expect here...

How have you calculated the neutral current out of interest?

 

[uksparks]

How have you calculated the neutral current out of interest?

Well thats based on what I measured at the cutout with a clamp meter round the tails. See photos below. I did sit for around 5 mins to see if it fluctuated etc... The neutral was reading 8A.

 

[spark 68]

Your max IM I calculated at about 53 to 54 A taking into account adding a proposed further 60A load to one of the low loaded phases assuming say L1=8A,L2 =25A, L3=68A

That is just from the information you have given, your PME rod/s in this case would need to be about 3 ohms

This is only a quick and rough calc with using assumed values

 

[telectrix]

maybe what's needed is a 3 phase charger. :49:

 

[uksparks]

Your max IM I calculated at about 53 to 54 A taking into account adding a proposed further 60A load to one of the low loaded phases assuming say L1=8A,L2 =25A, L3=68A

That is just from the information you have given, your PME rod/s in this case would need to be about 3 ohms

This is only a quick and rough calc with using assumed values

How did you come to that? can you show me the calculation how you did it please, my one came out different...?

 

[Simonslimline]

How did you come to that? can you show me the calculation how you did it please, my one came out different...?

Im=√((IL1-0.5(IL2+IL3))²+(0.866(IL2-IL3))²

I got 53.57 Amps.

 

[spark 68]

How did you come to that? can you show me the calculation how you did it please, my one came out different...?

I cheated lol I used Tony's XL spreadsheet to calc the N current

Simon above did it long hand

 

[Simonslimline]

I cheated lol I used Tony's XL spreadsheet to calc the N current

Simon above did it long hand

I have an Excel spreadsheet as well. Wanted to show the way to calculate it though. Either way its the same answer

 

[uksparks]

I cheated lol I used Tony's XL spreadsheet to calc the N current

Simon above did it long hand

i did it this way and got a different figure...

Im=√((8-0.5(25+68))²+(0.866(25-68))²

I wonder if i am typing it wrong on the calculator?

Can someone else try this method please.

 

[spark 68]

I have an Excel spreadsheet as well. Wanted to show the way to calculate it though. Either way its the same answer

I have enough trouble posting on here normally with IE11 lol without trying to insert symbols lol

 

[Simonslimline]

I have enough trouble posting on here normally with IE11 lol without trying to insert symbols lol

i use this Type mathematical symbols - online keyboard

 

[Simonslimline]

i did it this way and got a different figure...

Im=√((8-0.5(25+68))²+(0.866(25-68))²

I wonder if i am typing it wrong on the calculator?

Can someone else try this method please.

Can do it like this as well

In=√((Ia²+Ib²+Ic²)-((Ia*Ib)+(Ia*Ic)+(Ib*Ic)))

OR

x = A cos 0 + B cos 120 + C cos 240
y = A sin 0 + B sin 120 + C sin 240
N = √(x²+y²)

 

[Simonslimline]

i did it this way and got a different figure...

Im=√((8-0.5(25+68))²+(0.866(25-68))²

I wonder if i am typing it wrong on the calculator?

Can someone else try this method please.

Must be how you are typing it mate. What answer are you getting?