3 lead low Err5 code Fluke 1664FC

[Simthespark]

Hi All

New to this forum, have read the posts on here from google but only recently signed up. I'm having some issues and some input would be very handy.

Testing at my house. I have a TN-S supply. Cutout is circa 1980s, cable is circa 1940s. Lead PILC incomer encased in a 1-¼" (32mm ish) old steel conduit going underground and disappearing towards street. Smart meter straight to CCU DP isolator.

Earth is provided via BS951 clamp onto this steel conduit. Ze 0.65Ω PFC 0.379kA measured on 2 lead high.
10mm² bonding for water & gas.
All final circuits are fed via RCBOs bar the garage supply which is on an MCB.

So, I have some final circuits just like any dwelling: Cooker radial, socket radials, socket rings, lighting radials, etc. When I carry out a 3 lead low Zs test on these I get an 'Err5' code flashing along with reading such as 5.37Ω, 7.28Ω, etc very high. I can't seem to get a good reading at all.

When I test the Ze on 3 lead low it does the same, I did this just to see what it would do. The Ze and Zdb are exactly the same despite the incoming services being metallic, thought the Zdb might be lower but who knows.

I've used this particular tester on lots of different installs and it doesn't seem to give me this code anywhere else apart from at my house. I've tried using a borrowed Fluke 1662 and Megger MFT 1721. The Fluke 1662 flashes the same 'Err5' code and the Megger doesn't give a code just an outrageously high reading. I obviously can't test these final circuits on 2 lead high as they're all RCBO's apart from the garage supply which tests out fine on 2 lead high again but not on 3 lead low.

Final circuits have been dead tested R1+R2, IR and are all good, polarity correct, etc.

A real example from the tests:
Cooker B32A Type A RCBO
R1+R2 0.04Ω
Zs 5.37Ω

From what I understand the 'Err5' code means 'noisy AC' so could be appliances plugged in etc. I tried these test with no load on circuits and got the same results.

What could be the issue here? Any advice would be helpful...

Many thanks,
Sim

 

[westward10]

You have a PILC incomer yet the earthing conductor is connected to the steel conduit this is contained in?

 

[Simthespark]

You have a PILC incomer yet the earthing conductor is connected to the steel conduit this is contained in?

Indeed, notified DNO they came out and checked it all out. They took a Ze as well and said it was fine. There's not enough lead on show to connect to I'll see if I can upload a pic. I asked them about this and they said it was common in my area to conceal these PILCs in steel conduit up to the foundation boundary and at that point the steel conduit and PILC sheath are connected.

 

[westward10]

I would suggest if it is for protection then that connection is tenuous nevertheless your Ze is fine.

 

[Simthespark]

I would suggest if it is for protection then that connection is tenuous nevertheless your Ze is fine.

Yep thats what I thought but the DNO guys onsite said its fine and left, couldn't do much about that and ended up not being too bothered cos the Ze was ok. Any take on the testing issues above?

 

[Mike Johnson]

@Simthespark Do you have any appliances hard wired into the circuits, therefore not disconnected?

"I tried these test with no load on circuits and got the same results." sorry if I teaching you to suck eggs, but no load on the circuits tends to suggest you think having the appliance switched off is sufficient?

 

[Simthespark]

I would suggest if it is for protection then that connection is tenuous nevertheless your Ze is fine.

@Simthespark Do you have any appliances hard wired into the circuits, therefore not disconnected?

"I tried these test with no load on circuits and got the same results." sorry if I teaching you to suck eggs, but no load on the circuits tends to suggest you think having the appliance switched off is sufficient?

Hi,

No problem any suggestions welcome at this point can’t find a solution myself. Yes appliances were off via DP isolators (FCU) and lamps disconnected in lighting circuit (GU10 LEDs) all removed. Tedious but still didn’t work.

 

[loz2754]

Are you able to get a proper Zs test result on the garage which is supplied by an MCB, so you can use the 2 high setting?

 

[Thomas knott]

Hi All

New to this forum, have read the posts on here from google but only recently signed up. I'm having some issues and some input would be very handy.

Testing at my house. I have a TN-S supply. Cutout is circa 1980s, cable is circa 1940s. Lead PILC incomer encased in a 1-¼" (32mm ish) old steel conduit going underground and disappearing towards street. Smart meter straight to CCU DP isolator.

Earth is provided via BS951 clamp onto this steel conduit. Ze 0.65Ω PFC 0.379kA measured on 2 lead high.
10mm² bonding for water & gas.
All final circuits are fed via RCBOs bar the garage supply which is on an MCB.

So, I have some final circuits just like any dwelling: Cooker radial, socket radials, socket rings, lighting radials, etc. When I carry out a 3 lead low Zs test on these I get an 'Err5' code flashing along with reading such as 5.37Ω, 7.28Ω, etc very high. I can't seem to get a good reading at all.

When I test the Ze on 3 lead low it does the same, I did this just to see what it would do. The Ze and Zdb are exactly the same despite the incoming services being metallic, thought the Zdb might be lower but who knows.

I've used this particular tester on lots of different installs and it doesn't seem to give me this code anywhere else apart from at my house. I've tried using a borrowed Fluke 1662 and Megger MFT 1721. The Fluke 1662 flashes the same 'Err5' code and the Megger doesn't give a code just an outrageously high reading. I obviously can't test these final circuits on 2 lead high as they're all RCBO's apart from the garage supply which tests out fine on 2 lead high again but not on 3 lead low.

Final circuits have been dead tested R1+R2, IR and are all good, polarity correct, etc.

A real example from the tests:
Cooker B32A Type A RCBO
R1+R2 0.04Ω
Zs 5.37Ω

From what I understand the 'Err5' code means 'noisy AC' so could be appliances plugged in etc. I tried these test with no load on circuits and got the same results.

What could be the issue here? Any advice would be helpful...

Many thanks,
Sim

Error 5 is noisy ac, which can be caused by lots of things. Try running a long lead (r2) back to the main earth bond and try out the 3 lead test again. That would mean the issue is on your circuits and not the supplier.

You got any large antennas nearby? Your wiring could have a signal inducted via that.

The only way around this is to remove rcbo and test via a MCB with high current. Otherwise you've most likely got a piece of equipment dumping to earth.

 

[Simthespark]

Are you able to get a proper Zs test result on the garage which is supplied by an MCB, so you can use the 2 high setting?

Yeah the Zdb at the garage measure fine on 2 high, 3 low same problem again with error 5 code

 

[Simthespark]

Error 5 is noisy ac, which can be caused by lots of things. Try running a long lead (r2) back to the main earth bond and try out the 3 lead test again. That would mean the issue is on your circuits and not the supplier.

You got any large antennas nearby? Your wiring could have a signal inducted via that.

The only way around this is to remove rcbo and test via a MCB with high current. Otherwise you've most likely got a piece of equipment dumping to earth.

I've tried 3 low on just the incomer. What I mean by that is a Ze test with installation isolated, earthing conductor removed and croc clipped on to. L & N probes oon incoming side of main switch. Still get an error 5 code. I will give the long lead a try though to see if that does anything.

No large antennas that I'm aware of nearby.

Removing RCBOs and using MCB on 2 high for test purposes sounds like it would work too.

 

[Mike Johnson]

Did this get resolved in the end?

 

[Thomas knott]

So its noisy ac from the supplier. Maybe you've got a welding shop nearby or something like that!

Only option is to put a MCB to zs or calculated zs is also fine in this situation.

You can fit noise reducing filters to supplies but I've no experience with that. Worth phoning up the energy supplier and asking some questions, it could damage equipment on your side.

I've tried 3 low on just the incomer. What I mean by that is a Ze test with installation isolated, earthing conductor removed and croc clipped on to. L & N probes oon incoming side of main switch. Still get an error 5 code. I will give the long lead a try though to see if that does anything.

No large antennas that I'm aware of nearby.

Removing RCBOs and using MCB on 2 high for test purposes sounds like it would work too.

 

[timhoward]

This lesser known technique can be used for RCBO protected circuits, allowing a high current test to be used.
It's a good one to have in the bag, even if not used too often.
Obviously great care is needed not to forget to remove the link afterwards!