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Wiring the studio
Old 2 weeks ago
  #1
Here for the gear
 

Wiring the studio

Hi all,

I’m in the process of planning my new studio build. It’s part of the house, what used to be the garden but has been covered up and now a new room. The sockets in this room are on the same circuit as the living room, which isn’t ideal.

I also have a mixture of 240V and 120V equipment (from the UK but moved to Ecuador, which is the same as US power). Without getting into the discussion of re-buying my gear, I want to have a combination of both 120 and 240V sockets in the studio.

Long story short, I’ve done a bunch of reading and thinking and I feel that having a sub panel From a pair of breakers from the main panel, just for the studio, might be good. That way I achieve the following:

1) dedicated lines for the gear to avoid interference with stuff in rest of house.
2) additional breakers to get 240V power alongside the 120, as there aren’t many free breakers in the main panel.

Where I get a little lost is in the exact means/best way of doing it. I have a worker here who will carry our all of the electrical work, but he isn’t audio- literate, and being Ecuador (with huge respect for the workers here), he might try take shortcuts in a typically South-American manner, defeating the purpose altogether. I’m not very knowledgeable in this stuff, aside from the basics and what I’ve been reading.

Questions I have are things such as following:

1) how to run the cable through to the new room. All of the current wiring passes through tubing (I guess what you call conduit) in the walls. It’s not clear the exact route of the current cables into the studio, but whatever the case, the space in the tubing isn’t big enough to pass through new cables. He has suggested passing it through with the cabling for the lighting... seems like a good idea, but is it safe/a good option in terms of interference?

2) Grounding. I’m assuming that I need to feed the two lives, neutral, AND ground through to sub panel. Then at the sub panel, the neutral should NOT be connected to the ground. Please correct me if this is wrong. Then, is an additional grounding rod needed for this sub panel? Or is the connection back to the house good enough?

3) in my description above, Does anyone have any comments/suggestions/other ideas? In terms of ‘code’, they are pretty relaxed here, so if I approach it as being sound for US standards, there won’t be any issues here.

Thank you everyone!
Old 2 weeks ago
  #2
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in the US system:
from the main panel to the sub-panel
Hot (Black), Hot (Red), Neutral (White), Safety Ground (Green)(gr/yel)

The Safety Ground connects to the Neutral at the main panel.
240V is Black & Red

* * * * * * * * * *
in the sub-panel the Neutral bus is insulated from the case. sometimes there is a hidden grounding screw that needs to be removed.
Old 1 week ago
  #3
Here for the gear
 

Thanks for confirming this - would I need a dedicated grounding rod for the sub panel?

And does anyone else have any suggestions as to how to feed the cables through to the studio? Would utilizing the routes of the lighting cables be safe/ok? Or do we need to rethink that?
Old 1 week ago
  #4
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Papanate's Avatar
 

Quote:
Originally Posted by drunmersteve View Post
Thanks for confirming this - would I need a dedicated grounding rod for the sub panel?
Absolutely. Keeping the room on it's own grounding is a good idea.

Quote:
And does anyone else have any suggestions as to how to feed the cables through to the studio? Would utilizing the routes of the lighting cables be safe/ok? Or do we need to rethink that?
To pre-existing wiring in the new room? I would start with where the builder/electrician tapped off the existing wiring in the house and run cabling back to the Breaker Box.
Old 1 week ago
  #5
Here for the gear
 

Quote:
Originally Posted by Papanate View Post
To pre-existing wiring in the new room? I would start with where the builder/electrician tapped off the existing wiring in the house and run cabling back to the Breaker Box.
That’s the problem. We know the route the electricity takes to get to the studio room, but closer to the breaker box, there just isn’t enough space in the internal wall tubing to pass new cables. Therefore we are trying to figure a new route (which is already pre-existing) to pass the new cable from main breaker to sub panel. Which is why the route of the lighting was suggested... if it is safe?
Old 1 week ago
  #6
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by drunmersteve View Post
Thanks for confirming this - would I need a dedicated grounding rod for the sub panel?
NO...Any sub panel with 240V has 4 wires; two hot, neutral & ground..
IF you use another ground rod it STILL needs to be connected to the main ground..
Old 1 week ago
  #7
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Papanate's Avatar
 

Quote:
Originally Posted by nosebleedaudio View Post
NO...Any sub panel with 240V has 4 wires; two hot, neutral & ground..
IF you use another ground rod it STILL needs to be connected to the main ground..
I did not know this. It does make sense though.
Old 1 week ago
  #8
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by Papanate View Post
I did not know this. It does make sense though.
IF you don't connect the two grounds then you will not have a ground fault current path, plus you could have a voltage potential between them..Bad idea..Plus its NEC..
Old 1 week ago
  #9
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Quote:
Originally Posted by nosebleedaudio View Post
IF you use another ground rod it STILL needs to be connected to the main ground..
Yes I understand this much, that the ground in the sub panel has to be fed back to main ground. I intend on linking all four cables between main and sub panel. I notice your emphasis on IF I do another ground rod (Appreciate this has to be connected to main earth).

So it isn’t necessary? And if not necessary, why would I do it? Would the ground link back to the main panel not be sufficient?
Old 1 week ago
  #10
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by drunmersteve View Post
Yes I understand this much, that the ground in the sub panel has to be fed back to main ground. I intend on linking all four cables between main and sub panel. I notice your emphasis on IF I do another ground rod (Appreciate this has to be connected to main earth).

So it isn’t necessary? And if not necessary, why would I do it? Would the ground link back to the main panel not be sufficient?
Just that IF you choose to use Two ground rods they still need to be connected, NOT required, two ground rods that is...
Old 1 week ago
  #11
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Ok great good to know. What’s the advantage of having it? Is it just additional security?
Old 1 week ago
  #12
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by drunmersteve View Post
Ok great good to know. What’s the advantage of having it? Is it just additional security?
If I was going to add a 2nd or 3rd ground rod it would be at the MAIN panel..
Old 1 week ago
  #13
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Quote:
Originally Posted by drunmersteve View Post
Thanks for confirming this - would I need a dedicated grounding rod for the sub panel?
No, no, no!
the path back to the ground rod is:
Sub-panel
Safety Ground/Protective Earth wire
Main-panel
grounding rod
Old 1 week ago
  #14
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Quote:
Originally Posted by nosebleedaudio View Post
If I was going to add a 2nd or 3rd ground rod it would be at the MAIN panel..
Exactly!
you can have as main ground rods as you like.
but they all need to be wired together at connect to the Main Panel at a single point.

* * * * * * * * * * *
note that grounding rods have nothing to do with day-to-day AC power quality.
they are there for safety during unusual high voltage events and to keep the Neutral at about the same potential as the swimming pool.
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