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BANGKOK 21 July 2019 17:43
Yellowtail

Electrical Service

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1 minute ago, Crossy said:

OK L2 and L3 are probably showing "phantom" voltages and are just floating.

 

I agree every 3rd breaker should be live with that configuration, if you are seeing hot outputs (are they still hot with the breaker off?) then something odd is going on which needs looking at before you re-connect the 3-phase supply.

 

Haven't checked it with the breaker off. I'll have another look when I get back. 

 

 

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3 minutes ago, Yellowtail said:

Is there any way to check the quality of the ground/earth at the panel?

 

You really need the correct test meter (you can't do it with a multimeter)

 

There is an alternative, but it will scare your wife.

  • Disconnect the wire going to the rod.
  • Get a small (say 15W) incandescent lamp (a regular tungsten lamp).
  • Connect one end of the lamp to the wire going to the rod.
  • Dab the other end of the lamp on to the incoming live (care please)
  • If the lamp lights then you have a "decent" ground (the brighter the light the better the ground).

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6 minutes ago, Crossy said:

 

You really need the correct test meter (you can't do it with a multimeter)

 

There is an alternative, but it will scare your wife.

  • Disconnect the wire going to the rod.
  • Get a small (say 15W) incandescent lamp (a regular tungsten lamp).
  • Connect one end of the lamp to the wire going to the rod.
  • Dab the other end of the lamp on to the incoming live (care please)
  • If the lamp lights then you have a "decent" ground (the brighter the light the better the ground).

That makes sense, thanks.

 

How can I check that the ground is not tied to neutral? 

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1 minute ago, Yellowtail said:

How can I check that the ground is not tied to neutral? 

 

With the main breaker OFF just use you meter on "ohms".

 

BUT

 

There ought to be a link N-E (MEN link) between the incoming neutral and the grounding system to be compliant with the current requirements and (since the incoming neutral isn't switched) this will show up in the above test.

 

From the photos, it does seem that there in NOT a MEN link (older installation). Your renovation of the system should include some form of earth-leakage protection on critical circuits (water heaters, outdoor outlets, outdoor lighting).

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2 hours ago, Crossy said:

 

With the main breaker OFF just use you meter on "ohms".

 

BUT

 

There ought to be a link N-E (MEN link) between the incoming neutral and the grounding system to be compliant with the current requirements and (since the incoming neutral isn't switched) this will show up in the above test.

 

From the photos, it does seem that there in NOT a MEN link (older installation). Your renovation of the system should include some form of earth-leakage protection on critical circuits (water heaters, outdoor outlets, outdoor lighting).

 

The MEN should be installed whether or not I upgrade to 3PH, correct?

 

Is this just something I can buy and screw in?

 

Thanks again

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3 hours ago, Yellowtail said:

The MEN should be installed whether or not I upgrade to 3PH, correct?

 

Yes, but!

 

You need to be a wee bit careful. Implementing the MEN link is easy, it's just a length of wire, as to whether you should is down to what the distribution network looks like.

 

Have a look at the power poles leading towards your transformer, if you see a ground strip running from the top (neutral) of the 4 low-voltage wires on every third or fourth pole then MEN is implemented, if you don't, it's not. 

 

My advice has always been, if you're not sure then don't add MEN to an existing installation.

 

 

 

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1 hour ago, Crossy said:

 

Yes, but!

 

You need to be a wee bit careful. Implementing the MEN link is easy, it's just a length of wire, as to whether you should is down to what the distribution network looks like.

 

Have a look at the power poles leading towards your transformer, if you see a ground strip running from the top (neutral) of the 4 low-voltage wires on every third or fourth pole then MEN is implemented, if you don't, it's not. 

 

My advice has always been, if you're not sure then don't add MEN to an existing installation.

 

 

 

1

 

I'll track down the transformer and take a few pictures, thanks!

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