phase rotation incorrect at origin of install .

[me2]

Hi all,
What are your views on phase rotation.
Whilst doing an eicr for a customer's premises I found that the phase rotation at the origin was anti clockwise .
the eicr form is asking for verification of phase sequences , which there is although anticlockwise .
What would you do there in the real world?
Would you :
1. tick it ( there is a sequence of phases verified )
2. cross it
3 . not verified

thanks in advance for your views

 

[Pete999]

Hi all,
What are your views on phase rotation.
Whilst doing an eicr for a customer's premises I found that the phase rotation at the origin was anti clockwise .
the eicr form is asking for verification of phase sequences , which there is although anticlockwise .
What would you do there in the real world?
Would you :
1. tick it ( there is a sequence of phases verified )
2. cross it
3 . not verified

thanks in advance for your views

You mean Phase Sequence, not Rotation don't you?

 

[me2]

yes sequence, but I tested it with my trusted phase rotation unit and found the sequence at origin to be anticlockwise . Now I do not know if DNO is required to provide a clockwise phase sequence or not .

 

[davesparks]

Hi all,
What are your views on phase rotation.
Whilst doing an eicr for a customer's premises I found that the phase rotation at the origin was anti clockwise .
the eicr form is asking for verification of phase sequences , which there is although anticlockwise .
What would you do there in the real world?
Would you :
1. tick it ( there is a sequence of phases verified )
2. cross it
3 . not verified

thanks in advance for your views

Phase rotation and phase sequence are two different things.
You are looking at the sequence for the EICR, not necessarily the rotation.

Phase rotation is either clockwise or anticlockwise.

Phase sequence is checking that L1 at the intake connects to every L1 terminal in the installation, L2 at the intake connects to every L2 terminal in the installation and L3 connects to every L3 terminal in the installation.

So despite the rotation being wrong the phase sequence can still be correct as long as the conductors dot get swapped around anywhere.
[automerge]1588261477[/automerge]

yes sequence, but I tested it with my trusted phase rotation unit and found the sequence at origin to be anticlockwise . Now I do not know if DNO is required to provide a clockwise phase sequence or not .

You cannot check phase sequence with a phase rotation tester.

Phase sequence is not a property of the origin, it is something checked throughout the whole installation.

 

[R-fur]

DNO meters are only in calibration if the rotation is correct. If the rotation is incorrect there is probably crossed tails between the meter and main switch.
Also be careful saying clockwise and anti clockwise. Traditional British phase rotation meters went anti clockwise for standard rotation while modern meters go clockwise for standard location.

 

[7029 dave]

When you say origin, can I ask where you tested from.

 

[me2]

When you say origin, can I ask where you tested from.

I tested on the outgoing side of the isolator that was just after the meter.
[automerge]1588268256[/automerge]
Thanks everyone for the answers so far.

 

[7029 dave]

IMO complete your report,advise the customer to contact their energy supplier, to address the phase rotation issue.

 

[me2]

IMO complete your report,advise the customer to contact their energy supplier, to address the phase rotation issue.

thanks dave ,I will do but the only potential problem that I see with that is that the customer will inccur more down time for his premises and the rotation of all the 3 phases motor will need to be reversed .

 

[7029 dave]

thanks dave ,I will do but the only potential problem that I see with that is that the customer will inccur more down time for his premises and the rotation of all the 3 phases motor will need to be reversed .

Understand the inconvenience of the down time, however the phase rotation can be reversed at the meter, L2L2 L3L3 swapped as complete pairs. No reversing is needed on the installation side.

 

[R-fur]

Can you trace the tails between the meter and the incoming side of the isolator.

 

[me2]

Can you trace the tails between the meter and the incoming side of the isolator.

yes right next to it, why?
[automerge]1588271646[/automerge]

Understand the inconvenience of the down time, however the phase rotation can be reversed at the meter, L2L2 L3L3 swapped as complete pairs. No reversing is needed on the installation side.

hi dave , I am not sure i follow what you mean here. surely if anything is reversed upstream (so to speak) the end appliances that rely on phase rotations for their direction (3 phases motors in this case) will be running in the opposite direction . Unless i am missing something obvious .

 

[7029 dave]

yes right next to it, why?
[automerge]1588271646[/automerge]

hi dave , I am not sure i follow what you mean here. surely if anything is reversed upstream (so to speak) the end appliances that rely on phase rotations for their direction (3 phases motors in this case) will be running in the opposite direction . Unless i am missing something obvious .

I cant explain the science, Marconi a member on here (the professor) is the man.
So im not even going to attempt.

 

[R-fur]

yes right next to it, why?

Because as I already said the meter is usually installed with standard rotation otherwise it is not within its certification. You are saying the rotation at the isolator is wrong. If the tails are straight then it is a DNO issue, if the tails are crossed then it is a customers issue. Albeit that they would need to pay the DNO to swap them.
Having non standard rotation in an installation is not a panic situation as long as every one electrical is aware of it.

 

[davesparks]

thanks dave ,I will do but the only potential problem that I see with that is that the customer will inccur more down time for his premises and the rotation of all the 3 phases motor will need to be reversed .

Have you checked the phase sequence? Is it consistent throughout the installation?

If all the motors are running the right way then either they have all had rotation corrected, it has been corrected elsewhere or there is a mistake in your testing
[automerge]1588273554[/automerge]

Understand the inconvenience of the down time, however the phase rotation can be reversed at the meter, L2L2 L3L3 swapped as complete pairs. No reversing is needed on the installation side.

That won't change the phase rotation problem that the OP thinks they have. It will only change the rotation at the meter.