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[D Edgcumbe]

Our church has acquired a former public school and are planning and starting renovations.  I started a thread at http://forums.prosoundweb.com/index.php/topic,154460.0.html

What should we be doing for electrical wiring?  Number of circuits in case they have events? Grounding (bonding)? Surge protection?  Anything else to do it right the first time?  Somewhere I read that the sound circuits should all be on one phase (3-phase system).  Im an electrical apprentice, with help from an electrician (who probably knows even less than me about sound stuff) and members from the church.

[Mike Sokol]

Our church has acquired a former public school and are planning and starting renovations.  I started a thread at http://forums.prosoundweb.com/index.php/topic,154460.0.html

What should we be doing for electrical wiring?  Number of circuits in case they have events? Grounding (bonding)? Surge protection?  Anything else to do it right the first time?  Somewhere I read that the sound circuits should all be on one phase (3-phase system).  Im an electrical apprentice, with help from an electrician (who probably knows even less than me about sound stuff) and members from the church.

Please post a picture of your electrical service panel. That will help get things started.

[D Edgcumbe]

Which one? lol
Actually not sure what you want by "service"
There's an 800A 208V 3PH service which splits to 200A disconnect and utility meter for "lighting" and 600A disconnect/meter for "heating", which then splits to about 4-5 (lost track) disconnects feeding panels for lighting and 6-7 disconnects feeding panels for heating respectively.  Most of the lighting/receptacles in the renovating part currently comes from one such panel, with plans of adding a 100A panel in the new kitchen from an unused heating disconnect, likely pull from that for new circuits.

[Mike Sokol]

Which one? lol
Actually not sure what you want by "service"
There's an 800A 208V 3PH service which splits to 200A disconnect and utility meter for "lighting" and 600A disconnect/meter for "heating", which then splits to about 4-5 (lost track) disconnects feeding panels for lighting and 6-7 disconnects feeding panels for heating respectively.  Most of the lighting/receptacles in the renovating part currently comes from one such panel, with plans of adding a 100A panel in the new kitchen from an unused heating disconnect, likely pull from that for new circuits.

I'm guessing this is old enough that it doesn't maintain separate grounds and neutral through the various sub-panels. If it doesn't have a neutral bus bar insulated from the box, then getting a quiet ground for audio could be a challenge. Since you're an electrical apprentice, see if you can open up a panel and take a picture of the ground and neutral bus. If all the ground and neutral wires are jammed in the same bus bar, then we need to do some thinking on how best to proceed.

[D Edgcumbe]

The original is about 50 years old.  I should have clarified Im in Canada, I haven't ever seen it here (doubting it was allowed) with "grounds" and neutrals combined, even in a service panel.  I will probably be there tomorrow and see what I can gather.

[Cailen Waddell]

Dave, I mentioned this in your other thread, and I think we all will be able to help, but for a review of best practices for electrical work for AVL, read the white paper here:
http://www.middleatlantic.com/resources/white-papers.aspx


Sent from my iPhone using Tapatalk

[Frank DeWitt]

Mike is the expert here but I will post a couple of things.
SurgeX is the way to go for surge protection. http://surgex.com/  They don't dump the surge down the ground wire. (You don't want that to happen because as a surge goes through a ground the voltage at the gear end of that ground will go up (Ohms law)  You will have equipment shields between that ground and other grounds and you can take out equipment that way.

BTW SurgeX seems to be in low demand on Ebay.  I have found some very good prices there.
BBTW  A lot of SurgeX products have remote control and delayed power up and down features built in.  Very nice for

If you will be pulling new wire in conduit twist the hot and common, then pull that twisted pr with a normal straight safety ground This will cut way down on a major cause of Ground loop noise.  from Ground Loops: The Rest of the Story
http://www.jensen-transformers.com/wp-content/uploads/2015/02/AES-Ground-Loops-Rest-of-Story-Whitlock-Fox-Generic-Version.pdf

You will need to register for this but it is free and worth the trouble.

Also you may want to use isolated ground outlets.  Not because you want a isolated ground system but because you don't want your outlet grounds connected to the conduit and thus to the building steel.

While you have the place apart, I would run a few BIG conduits from the platform to the booth location and to that other place you might put a booth.

Also run CAT5 everywhere.  It is cheep and you can use it for almost anything.  audio  DMX, computer, digital sound board Video, telephone,  and a lot more.  If you are already pulling CAT 5 someplace pull a spare.  Some day it will make someone smile.

[Mike Sokol]

The original is about 50 years old.  I should have clarified Im in Canada, I haven't ever seen it here (doubting it was allowed) with "grounds" and neutrals combined, even in a service panel.  I will probably be there tomorrow and see what I can gather.

Never ASSume what someone else wired 50 years ago. I've seen tons of mid-century (that's what they call the 60's now) electrical boxes with common neutrals and grounds here in the states. I know Canada is much more "ground aware" than us, but you'll still want to get eyes on everything. 

[Stephen Swaffer]

Something else to confirm-a 100 amp heating disconnect may or may not have a neutral run to it.  Before you decide to install a panel verify that you in fact have what you need there. 

If you can add a panel, then that is the best option-you can make sure your grounds and neutrals are done right.  If you need to use an existing panel, separating the grounds/neutrals is pretty straightforward, if a bit time consuming-the hardest part being getting a separate ground to the panel.

Another thing to watch for, if you have existing panels that have grounds/neutrals common is to make sure the box bonding screw is in fact in place.  When doing upgrades/converting panels to subpanels I find the bonding screw missing more often than not.

[Mike Sokol]

Another thing to accomplish is to isolate your EGC from the building steel. For instance, if use armored cable or conduit between the service panel and boxes (most commercial buildings do), and standard (non-isolated ground) receptacles, it's likely that your electrical grounds are bonded to building steel at multiple locations. This is compounded in modern construction that uses steel studs. If this is the case, then pulling two separate ground wires is a way to isolate your audio ground from the building ground. In the USA, this is secondary, building isolated ground is called a Technical Ground and typically colored Green with a Yellow stripe. The safety ground (EGC or Equipment Grounding Conductor) is solid Green. By using Isolated Ground Receptacles you can then keep your audio ground separate from the building steel, and bonded to a single service panel. Under no circumstances have different receptacles in your room connected to multiple service panels.

The thing to know is that you really don't need a perfectly quiet building ground as long as ALL outlet grounds are at equal voltage potential. And the best way to assure that is to isolate every receptacle's ground from local building steel, and get all EGC connections in a room into a single sub-panel. Frank's recommendation of twisting Hot and Neutral wires together is also a good one, but only if everything else is wired correctly. 

[ProSoundWeb Community]