Electrical problem after installing a sub-panel

[bbudd]

Hi

I just installed a sub-panel in our guest house to handle increased electric usage ( mostly the air con)

Connected the wire between the main shut off and the house panel and ran to sub-panel in the guest house and installed a ground out there

Now the florescent and LED lights in the main house are all "ghost lights"  -they always have a glow at night

Also seem to have a really high elect bill now-almost double

 

Any idea whats causing this and a recommended fix?

[lopburi3]

13 minutes ago, bbudd said:

Connected the wire

As in "one wire"?

[bbudd]

No-sorrry

2 aluminum wires-heavy gauge

similar to main house leads from pole/meter

installed second ground just for sub-panel rather than run from main

[Crossy]

Is your main house supplied with MEN? Have you added a second MEN link at your new board?

 

If you turn off the new board's main breaker do your ghost lights stop?

 

When you spliced in to the supply did you disconnect the cables at your main disconnect unit, any possibilty that they got reversed?

 

Check the polarity at your new board and your existing board just to be sure.

 

Photos of your existing and new boards with the lids off would be very handy.

[lopburi3]

By MEN he means neutral conductor attached to ground at terminal box (not done everywhere).   If you can take photos without putting yourself in danger can be helpful - Crossy knows his stuff.

Quote

MEN Connection · It is the link between the main earth terminal bar and the main neutral conductor bar.

 

[bbudd]

both main and sub are grounded to rods

not sure if turning off sub panel-haven't tried yet

as both wires are identical-theirs a chance they are reversed at sub panel

how would i go about checking polarity?

i'll take some pix

[Crossy]

@bbudd did you DIY this or get a local "electrician" to do it?

 

What test equipment do you have?

 

A neon screwdriver is a quick and easy way to check polarity. If you don't have one you should get one along with a cheap digital multimeter. Your local hardware store should be able to help with both.

 

[bbudd]

black wires to sub panel are connected to main feed wires at 100 Amp breaker

[bbudd]

have a couple multi meters

its all DIY-did all ,my own electrical back in Canada

mostly 110-220

[Crossy]

OK. Looks like No MEN anywhere.

 

At the new panel.

With your meter set to >220V AC

One probe on your earth bar(top right) other probe on the right hand incoming wire you should see 220V ish.

Conversely, between the left side incoming wire and the earth bar you should see about 0V.

As a final check measure between the incoming cables, again 220V.

 

 At the old panel. Do the same, should be the same result.

 

It's a bit worrying that you old panel has the grey (normally neutral) wires on the breakers and the black wires (normally live) on the neutral bar. But the electrons really don't care what colour the insulation is. 

[bbudd]

I'm a lot more used to having correctly color coded wireing

Should have run each feed separately -but  as I only had one length I just ran them as I did

 

Whats the advantage to MEN connector?

[bbudd]

Thanks for pointing me in the right direction

kinda had me stumped

 

Tomorrow will verify polarity at both panels and correct if necessary

 

Nice to have knowledgeable folks around for assistance-much appreciated

[Crossy]

3 minutes ago, bbudd said:

Whats the advantage to MEN connector?

 

MEN provides a metallic path from your earth bar to the transformer star point, a L-E fault will open the MCB rapidly, far more rapidly than a short L-Rod alone (if that opens it at all). But do NOT implement unless you KNOW your local network is set up for it (the neutral is earthed every 3rd pole or so).

 

By the way, I see no earth leakage protection (RCD,RCBO, GFCI) you should think about adding it to any "risky" cricuits, water heaters, outdoor lighting / outlets etc.

  

[lopburi3]

1 minute ago, Crossy said:

any "risky" cricuits, water heaters, outdoor lighting / outlets etc.

All circuits in my mind are risky - other than overhead lights perhaps.  Any outlet should have protection as even a scraped extension cord plugged into it could be deadly (and not a lot of fun even with an RCD - got that demerit badge).

[bbudd]

Thanks for pointing me in the right direction

kinda had me stumped

 

Tomorrow will verify polarity at both panels and correct if necessary

 

Nice to have knowledgeable folks around for assistance-much appreciated

 

Your right about the ground fault-I've been too complacent

Sort of  if-it aint- broke attitude-may as well do a proper job if I'm in there

 

LOL-even the overhead lighting is risky

Had a mouse chew the wire and it shorted to the ceiling grid

Melted the support wire and 3 rows of panels fell on the ground

Sure woke me up fast

 

[Steve&mem]

MEN link ?????  I have just been for a walk down the Soi, every 4th electric post has a steel cable coming down from the cables above to the ground. So it looks like I have a MEN system in my area, just taken off the cover of the distribution board and I don't see a MEN link inside, If that's a cable that connects between neutral bar to the ground bar if I understand it right.

The house has 3 ground rod's that I believe to be 3 meters into the ground. Do I need to put this link in or is it ok as is.

Here is a picture of the breaker/interrupt on the garden wall and a picture of the distribution board.

[Crossy]

37 minutes ago, Steve&mem said:

MEN link ?????

 

In order to create MEN you have to link the INCOMING neutral to the earth bar. The Thai way is to route the incoming neutral itself to the earth bar then run a cable from there to the incoming side of the main breaker. You have to do it this way if you want to pass the inspection for a permanent supply.

 

To be honest, with good solid grounding and an incoming RCBO I'd leave it as it is.

 

[Steve&mem]

5 minutes ago, Crossy said:

 

In order to create MEN you have to link the INCOMING neutral to the earth bar. The Thai way is to route the incoming neutral itself to the earth bar then run a cable from there to the incoming side of the main breaker. You have to do it this way if you want to pass the inspection for a permanent supply.

 

To be honest, with good solid grounding and an incoming RCBO I'd leave it as it is.

 

Thanks for that, I think I will leave alone 

[bbudd]

Thanks for pointing me in the right direction

kinda had me stumped

 

Tomorrow will verify polarity at both panels and correct if necessary

 

Nice to have knowledgeable folks around for assistance-much appreciated

 

Your right about the ground fault-I've been too complacent

Sort of  if-it aint- broke attitude-may as well do a proper job if I'm in there

 

LOL-even the overhead lighting is risky

Had a mouse chew the wire and it shorted to the ceiling grid

Melted the support wire and 3 rows of panels fell on the ground

Sure woke me up fast

 

[bbudd]

You were correct-the polarity at sub-panel was reversed

Fixed now and no more ghost lights

 

Thanks again

Much appreciated