Return to the CurtPalme.com main site CurtPalme.com Home Theater Forum
A forum with a sense of fun and community for Home Theater enthusiasts!
Products for Sale ] [ FAQ: Hooking it all up ] [ CRT Primer/FAQ ] [ Best/Worst CRT Projectors List ] [ Setup Tips & Manuals ] [ Advanced Procedures ] [ Newsletters ]

 
Forum FAQForum FAQ   SearchSearch   MemberlistMemberlist  Photo AlbumsPhoto Albums  RegisterRegister 
 MembershipClub Membership   ProfileProfile   Private MessagesPrivate Messages   Log inLog in 
Blu-ray disc release list and must-have titles. Buy the latest and best Blu-ray titles to show off in your home theater!

How to add an Isolation Transformer to AV system.Thanks Bob!
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8, 9, 10  Next
 
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> Home Theater Design & Construction
View previous topic :: View next topic  
Author Message
lovebohn



Joined: 16 Mar 2006
Posts: 181
Location: Wisconsin


PostLink    Posted: Mon Jan 18, 2010 8:31 pm    Post subject: Reply with quote


        Register to remove this ad. It's free!
No there is no main breaker on the sub panel.

There is the normal bus for the neutral/ground and then another separate bus that looks screwed to the panel. I will get a picture up soon.
Back to top
Nashou66



Joined: 12 Jan 2007
Posts: 16170
Location: West Seneca NY


PostLink    Posted: Mon Jan 18, 2010 8:45 pm    Post subject: Reply with quote

Yes we need to see the sub panel. if i have a chance i'll take a pic of how mine looks now.

Athansios

_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher


"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan

One Smart Dog!!!

Marquee High Performance Bellows now shipping!!
Marquee Modifications and Performance Enhancement
Marquee C-element and Bellow removal
Back to top
View user's photo album (1 photos)
macgyver655



Joined: 22 Aug 2007
Posts: 8508



PostLink    Posted: Mon Jan 18, 2010 9:22 pm    Post subject: Reply with quote

lovebohn

Do yourself a favor and call an electrician.

This is becoming to painful to read.
Back to top
Boilermaker



Joined: 21 May 2006
Posts: 527



PostLink    Posted: Tue Jan 19, 2010 12:14 am    Post subject: Reply with quote

OK.

Quote:
No there is no main breaker on the sub panel.


Since the NEC considers the secondary side of your xfmr a separately derived source, they require protection for the service feed to your sub panel. When you go to your local supply store, also get a fused disconnect that you can use right after the xfmr to feed the sub panel. Should be pretty cheap and just size it based on the wire size you use.

Quote:
Do yourself a favor and call an electrician.


But he would miss out on all the fun of this hobby! Also, he would have to find an electrician who has had experience in the installation of electrical distribution systems in OR's in hospitals. The average residential electrician is not familiar with isolated power systems.

Bob
Back to top
macgyver655



Joined: 22 Aug 2007
Posts: 8508



PostLink    Posted: Tue Jan 19, 2010 12:53 am    Post subject: Reply with quote

However, the average residential electrician is familiar with residential code which apparently is different from hospital code.
Back to top
lovebohn



Joined: 16 Mar 2006
Posts: 181
Location: Wisconsin


PostLink    Posted: Tue Jan 19, 2010 4:16 am    Post subject: Reply with quote

Ok here is a pic of the sub panel. Yes it is a mess and needs to be cleaned up, but it was thrown together to test and see if my power feed changes over to the main panel helped. You can see the small bus bar in the top right corner that is not used now.

Back to top
macgyver655



Joined: 22 Aug 2007
Posts: 8508



PostLink    Posted: Tue Jan 19, 2010 4:24 am    Post subject: Reply with quote

Well now we know why you have a hum.
Back to top
lovebohn



Joined: 16 Mar 2006
Posts: 181
Location: Wisconsin


PostLink    Posted: Tue Jan 19, 2010 4:30 am    Post subject: Reply with quote

Boilermaker wrote:
First, I will assume you have not yet installed your iso. xfmr., so the problem you just described is with normal power fed from your sub panel.

If this is correct, turn off the 20A breaker feeding your Grafix Eye panel. Then, at the sub panel carefully remove the ground wire from the ground bar for this circuit. Now, using a VOM, measure the resistance between neutral and this ground wire. You may need to use the highest setting on your VOM. What did you measure?

Now, with the ground wire still disconnected, switch your VOM to AC volts at the lowest setting, switch the breaker back on, and measure the voltage between this disconnected ground wire and the neutral buss. What did you measure?

Bob


Ok here are my results

GE (Grafik Eye) breaker off ground removed from neutral bus bar = .8 ohms

Circuit breaker off = .046 volts AC
Circuit breaker on, GE lights off 24.6 volts
Circuit breaker on, GE lights on 43.1 volts

Other thing if i touch the ground wire to the other grounds which are connected to the bus bar i get .001 volts

Now i just have a simple digital VOM so it could not be exact, there are no settings just auto mode.

Looks like i need to look over my GE wiring!
Back to top
lovebohn



Joined: 16 Mar 2006
Posts: 181
Location: Wisconsin


PostLink    Posted: Tue Jan 19, 2010 4:32 am    Post subject: Reply with quote

macgyver655 wrote:
Well now we know why you have a hum.



Like i said above the sub panel did not look like this before the weekend (new feeds in, old ones out) and had the same hum. I'm not going to trim wires until i know for sure what direction I'm going.

.....and none of the grounds touch each other or the panel.
Back to top
macgyver655



Joined: 22 Aug 2007
Posts: 8508



PostLink    Posted: Tue Jan 19, 2010 4:39 am    Post subject: Reply with quote

The neatness is not what I was referring to. The box is incorrectly wired. But I'm in observation mode only so I'll keep my mouth shut......... Very Happy
Back to top
MikeEby



Joined: 24 Jun 2007
Posts: 5236
Location: Osceola, Indiana


PostLink    Posted: Tue Jan 19, 2010 4:59 am    Post subject: Reply with quote

macgyver655 wrote:
The box is incorrectly wired. But I'm in observation mode only so I'll keep my mouth shut......... Very Happy


Is it ok to connect the grounds to neutral? Or should be ground be connected to bus bar attached to the case, the one currently not being used?

Mike

_________________
Doing HD since the last century!
Back to top
macgyver655



Joined: 22 Aug 2007
Posts: 8508



PostLink    Posted: Tue Jan 19, 2010 5:01 am    Post subject: Reply with quote

MikeEby wrote:


Is it ok to connect the grounds to netural?

Mike


In a sub panel, absolutely NOT.
Back to top
MikeEby



Joined: 24 Jun 2007
Posts: 5236
Location: Osceola, Indiana


PostLink    Posted: Tue Jan 19, 2010 5:05 am    Post subject: Reply with quote

macgyver655 wrote:
MikeEby wrote:


Is it ok to connect the grounds to netural?

Mike


In a sub panel, absolutely NOT.


I didn't think so.... Smile I was trying to be nice.

Mike

_________________
Doing HD since the last century!
Back to top
Nashou66



Joined: 12 Jan 2007
Posts: 16170
Location: West Seneca NY


PostLink    Posted: Tue Jan 19, 2010 6:08 am    Post subject: Reply with quote

Lovbohn, you need to take the bare wires out of the neutral bus and put them into the Ground bar. Now i assume you do not have the Iso connected yet. After you move the grounds to the proper location see if you have a hum. I bet its gone after. But when you add the Iso you need to connect the ground from the Iso
to that ground bar in your panel . if there is a green bonding screw in your neutral bus removed it, i don't see one but i am saying it to be sure.

Here is a pic of my sub panel.

For some reason it did not upload rotated correctly.




As you can se i have the neutral from the iso and one hot, i could have brought two hots from the same
location but it was easier to just jump the Hot to get it to the other Bus. the ground bar is also connected to the ground in the iso. I removed the green bonding screw from the neutral to isolate the GROUND form it. that is why you have hum now if that is how you had it hooked up before.

Athanasios

_________________
Don't blame your underwear for your crooked ass~ unknown Greek philosopher


"Republicans believe every day is the Fourth of July, but the Democrats believe every day is April 15." --- President Reagan

One Smart Dog!!!

Marquee High Performance Bellows now shipping!!
Marquee Modifications and Performance Enhancement
Marquee C-element and Bellow removal
Back to top
View user's photo album (1 photos)
macgyver655



Joined: 22 Aug 2007
Posts: 8508



PostLink    Posted: Tue Jan 19, 2010 6:57 am    Post subject: Reply with quote

Nashou66 wrote:
Lovbohn, you need to take the bare wires out of the neutral bus and put them into the Ground bar. Now i assume you do not have the Iso connected yet. After you move the grounds to the proper location see if you have a hum. I bet its gone after. But when you add the Iso you need to connect the ground from the Iso
to that ground bar in your panel . if there is a green bonding screw in your neutral bus removed it, i don't see one but i am saying it to be sure.

Here is a pic of my sub panel.

For some reason it did not upload rotated correctly.




As you can se i have the neutral from the iso and one hot, i could have brought two hots from the same
location but it was easier to just jump the Hot to get it to the other Bus. the ground bar is also connected to the ground in the iso. I removed the green bonding screw from the neutral to isolate the GROUND form it. that is why you have hum now if that is how you had it hooked up before.

Athanasios


I wouldn't be to proud Athan. I see some concerns there. Smile
Back to top
Boilermaker



Joined: 21 May 2006
Posts: 527



PostLink    Posted: Tue Jan 19, 2010 9:49 am    Post subject: Reply with quote

Wow - You really have a f---ed up mess!

GE (Grafik Eye) breaker off ground removed from neutral bus bar = .8 ohms

Circuit breaker off = .046 volts AC
Circuit breaker on, GE lights off 24.6 volts
Circuit breaker on, GE lights on 43.1 volts
Quote:


You should have an open circuit between ground and neutral and you have a short circuit (.8 ohms). This means that somewhere in your lighting system the ground and neutral are shorted. This will completely negate the function of your isolation xfmr, so this needs to be corrected before you hook up this load.

The fact that you have 43 volts indicates that one or more of your ground wires is actually acting like a neutral. It should be very close to zero!

In order to chase this down, you will need to keep the neutral disconnected and start by doing a continuity check on each and every part of your lighting circuit - one at a time.

Your sub panel looks like it is all ready to go with that second buss. You need to confirm, however that it is mounted on insulated standoffs.

Whatever you do, don't hire the same residential electrician that wired your panel! (just had to add that, macgyver655!). It looks more like a rats nest than a panel.


Bob
Back to top
lovebohn



Joined: 16 Mar 2006
Posts: 181
Location: Wisconsin


PostLink    Posted: Tue Jan 19, 2010 2:46 pm    Post subject: Reply with quote

macgyver655 wrote:
MikeEby wrote:


Is it ok to connect the grounds to netural?

Mike


In a sub panel, absolutely NOT.


I feel like a dumb ass! I will get that switched around and see how things sound tonight.

You would have thought the guy who did my final home inspection would have noticed that. Goes to show what a small town building inspector can over look on a new home. BTW I did have a few master electricians help on the build. Enough excuses.

Mac and Bob thanks for staying on this tread.

Dave
Back to top
Boilermaker



Joined: 21 May 2006
Posts: 527



PostLink    Posted: Tue Jan 19, 2010 4:28 pm    Post subject: Reply with quote

Yes, they should absolutely be separated - Make sure that the neutral is isolated from the panel enclosure.
The only place that ground and neutral should be connected is at your main service entry panel.

In the case of your subpanel, after you install your xfmr. your ground and neutral will be completely isolated wjich is why it is considered a separately derived source, just as though it came from a different power company.

Let us know when you begin installing your xfmr.

Bob
Back to top
macgyver655



Joined: 22 Aug 2007
Posts: 8508



PostLink    Posted: Tue Jan 19, 2010 5:13 pm    Post subject: Reply with quote

lovebohn wrote:
macgyver655 wrote:
MikeEby wrote:


Is it ok to connect the grounds to netural?

Mike


In a sub panel, absolutely NOT.


I feel like a dumb ass! I will get that switched around and see how things sound tonight.

You would have thought the guy who did my final home inspection would have noticed that. Goes to show what a small town building inspector can over look on a new home. BTW I did have a few master electricians help on the build. Enough excuses.

Mac and Bob thanks for staying on this tread.

Dave



Your going to have to run a solid copper ground wire from the gnd bar back to the main panel before you switch those gnd lines over.
Back to top
lovebohn



Joined: 16 Mar 2006
Posts: 181
Location: Wisconsin


PostLink    Posted: Tue Jan 19, 2010 6:20 pm    Post subject: Reply with quote

Ok, that was my plan. What else did you notice on Athanasios panel that did not look correct?

I'm all for constructive criticism if it helps me or my toys work better in the end.


Last edited by lovebohn on Tue Jan 19, 2010 7:08 pm; edited 1 time in total
Back to top
Display posts from previous:   
Post new topic   Reply to topic   Printer-friendly view    CurtPalme.com Forum Index -> Home Theater Design & Construction All times are GMT
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8, 9, 10  Next
Page 6 of 10
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum