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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Jamin Lynch on October 16, 2017, 03:41:14 PM

Title: Power Distro Cabling Question
Post by: Jamin Lynch on October 16, 2017, 03:41:14 PM
I have a power distro with a 50amp California twist lock connector on the end of the my supply cable. Single phase. The house has Cam Lock connectors.   

I know it's not good practice to use Cam Lock feeds without the outside rubber jacket.

What would be a good and safe way to get from Cam Lock to a 50amp California connector?

Thanks
Title: Re: Power Distro Cabling Question
Post by: Thomas Lamb on October 16, 2017, 03:59:38 PM
how many amp breaker feeds the cam locks?

You need a main distro that is capable of that amperage with the appropriate size cable feeding it. It will also need CS connector outputs with the appropriate 50 amp dual pole breakers.

Something similar to this.

https://www.motionlabs.com/wp-content/uploads/169.jpg
Title: Re: Power Distro Cabling Question
Post by: TJ (Tom) Cornish on October 16, 2017, 04:57:50 PM
I have a power distro with a 50amp California twist lock connector on the end of the my supply cable. Single phase. The house has Cam Lock connectors.   

I know it's not good practice to use Cam Lock feeds without the outside rubber jacket.

What would be a good and safe way to get from Cam Lock to a 50amp California connector?

Thanks
Equipment being made by a listed shop aside, you have two problems to solve - camlok to 50A, and 50A OCPD to protect your feeder (this is needed even if you have a 50A main beaker if your feeder is longer than 10').

Solving the former requires male camlok connectors mounted on some kind of enclosure, and the wires from that enclosure going through suitable conduit to a small load center with one or more 50A breakers each protecting 50A receptacle.

You would then need single-conductor camlok to camlok feeder either fully rated for the size of the disconnect (200A or whatever), or you could get away with smaller #4 SC wire if your step-down box is less than 10' from the venue camlok disconnect.

NEC 2017 requires all distro equipment to be listed, so whatever you make may not solve all your issues.
Title: Re: Power Distro Cabling Question
Post by: Tim McCulloch on October 16, 2017, 05:09:09 PM
Jamin, it depends on how picky your AHJ and if you need UL/CSA listed assemblies...

Tom L hits the first important point - the ampacity of the feeding connection.  NEC (520) allows short tails or feeders to be under-sized; how much is determined by the length of those tails or connecting feeder.  Depending on the ampacity of the feeding connection you might get away with single cam conductors as small as #2, but might have to move up to #0.

You need an intermediate overcurrent protection device (50 amp beaker) between the Cams and the CS.  Exactly how you'd do this is up to you, but you need to get the feeder conductors into the box and a panel mount CS outlet.

You could probably build it yourself for $250 or so or pay Motion Labs or LEX or someone else $750 to build it for you and know it will have a UL sticker on it.
Title: Re: Power Distro Cabling Question
Post by: Jamin Lynch on October 16, 2017, 05:35:01 PM
Jamin, it depends on how picky your AHJ and if you need UL/CSA listed assemblies...

Tom L hits the first important point - the ampacity of the feeding connection.  NEC (520) allows short tails or feeders to be under-sized; how much is determined by the length of those tails or connecting feeder.  Depending on the ampacity of the feeding connection you might get away with single cam conductors as small as #2, but might have to move up to #0.

You need an intermediate overcurrent protection device (50 amp beaker) between the Cams and the CS.  Exactly how you'd do this is up to you, but you need to get the feeder conductors into the box and a panel mount CS outlet.

You could probably build it yourself for $250 or so or pay Motion Labs or LEX or someone else $750 to build it for you and know it will have a UL sticker on it.

My distro has a 50amp main breaker built in.

I'll need to see what size breakers the venue is using for the cam lock feeds. The feeder cable run would be about 50ft. I'll need to go measure.

So I would need to build or buy some kind of "device" that will get me from the house cam locks to my 50amp California plug?

Would I need cable sized for the house feeder breaker even if I have a 50amp main breaker in my distro?



Title: Re: Power Distro Cabling Question
Post by: Rob Spence on October 17, 2017, 12:29:20 AM
My distro has a 50amp main breaker built in.

I'll need to see what size breakers the venue is using for the cam lock feeds. The feeder cable run would be about 50ft. I'll need to go measure.

So I would need to build or buy some kind of "device" that will get me from the house cam locks to my 50amp California plug?

Would I need cable sized for the house feeder breaker even if I have a 50amp main breaker in my distro?

If any part of the feed to your distro is rated for less than the next upstream breaker (like, for instance, the California connector) then there needs to be a proper breaker protecting the downstream (California )connector.


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Title: Re: Power Distro Cabling Question
Post by: Jamin Lynch on October 17, 2017, 08:00:11 AM
If any part of the feed to your distro is rated for less than the next upstream breaker (like, for instance, the California connector) then there needs to be a proper breaker protecting the downstream (California )connector.


Sent from my iPad using Tapatalk Pro

Thanks Rob. Makes since.

I'm just trying find a good/safe way to get from the house cam locks to my distro which has a 50amp California plug
Title: Re: Power Distro Cabling Question
Post by: Tim McCulloch on October 17, 2017, 11:35:16 AM
Thanks Rob. Makes since.

I'm just trying find a good/safe way to get from the house cam locks to my distro which has a 50amp California plug

In a nutshell, CamLok ins to 50 amp breaker to CS outlet. 
Title: Re: Power Distro Cabling Question
Post by: Mark Cadwallader on October 17, 2017, 11:51:07 AM
The Indu-electric "Cube" model 18 looks like it is another pre-made camlock to Calif. 50A device meeting your needs.
Title: Re: Power Distro Cabling Question
Post by: Jamin Lynch on October 17, 2017, 01:38:16 PM
I'm going to be working there often, so I think what I'll do is get them to install a 50amp California connector for me to plug into that's on a 50 amp breaker in the service panel.

That should solve the issue wouldn't it?
Title: Re: Power Distro Cabling Question
Post by: TJ (Tom) Cornish on October 17, 2017, 01:59:46 PM
I'm going to be working there often, so I think what I'll do is get them to install a 50amp California connector for me to plug into that's on a 50 amp breaker in the service panel.

That should solve the issue wouldn't it?
Yes, and for considerably less cost than a listed portable device and feeder to do the step-down.
Title: Re: Power Distro Cabling Question
Post by: Jeff Hague on November 15, 2017, 04:18:40 PM
If any part of the feed to your distro is rated for less than the next upstream breaker (like, for instance, the California connector) then there needs to be a proper breaker protecting the downstream (California )connector.


Sent from my iPad using Tapatalk Pro

I used to use 50amp Calis on 50' 6/4 SO feeders that fed rack mounted distros in my amp racks.. This was an ideal solution when working with most generators that already had Calis.
But there were a few venues with a 200 amp 3 phase company switch on camlocks. For those I built a small panel with 50amp breakers and Calis. When needed I could rent #2 or #4 camlok to bare end tails to tie in to the panel so the main feeder was always rated for the higher service and I had 50amp breakers feeding (protecting) the 6/4.
Title: Re: Power Distro Cabling Question
Post by: Gene Hardage on November 15, 2017, 06:00:37 PM
I have a power distro with a 50amp California twist lock connector on the end of the my supply cable. Single phase. The house has Cam Lock connectors.   

I know it's not good practice to use Cam Lock feeds without the outside rubber jacket.

What would be a good and safe way to get from Cam Lock to a 50amp California connector?

Thanks

You need a few this to that adapters. 

Title: Re: Power Distro Cabling Question
Post by: Jeff Hague on November 15, 2017, 06:20:34 PM
You need a few this to that adapters.

Most of those adapters are 50a to 50a but you have to be careful with camlok - most services with camlok are 200a or more. You NEED a breaker to be SURE that you dont try to pull more than 50a on the components that are only rated for 50a.

In the picture I see camloks on what looks like 6guage cable - that could be bad news plugged in to a 200a service.
Title: Re: Power Distro Cabling Question
Post by: brian maddox on November 15, 2017, 07:12:19 PM
Most of those adapters are 50a to 50a but you have to be careful with camlok - most services with camlok are 200a or more. You NEED a breaker to be SURE that you dont try to pull more than 50a on the components that are only rated for 50a.

In the picture I see camloks on what looks like 6guage cable - that could be bad news plugged in to a 200a service.

The Camlocks in the picture appear to go straight to a panel with presumably appropriate sized breakers and then to a yellow box that i'm also going to assume has some kind of 50amp connector on it.

[Yes i used 'appear', 'presumably' and 'assume' in the same sentence...]

Of course the Ground and Neutral aren't turned around.  But i digress...
Title: Re: Power Distro Cabling Question
Post by: Tim McCulloch on November 15, 2017, 08:22:41 PM
The Camlocks in the picture appear to go straight to a panel with presumably appropriate sized breakers and then to a yellow box that i'm also going to assume has some kind of 50amp connector on it.

[Yes i used 'appear', 'presumably' and 'assume' in the same sentence...]

Of course the Ground and Neutral aren't turned around.  But i digress...

My 12 year old Code book does not *require* reversed ground or neutral connectors, rather it permits them.  Other allowed connection restrictions include physical interlocks to prevent conductor interchange and out-of-sequence connections, and restricting access and use to "qualified personnel" and posting of connection sequence at the point of service terminations.

Edit ps - NEC is "proposed" Code and the States and municipalities are free to adopt or not adopt code as they see fit.  They may also have codes that have more restrictive or more lenient practices.  The above may not apply in your locale, request clarification from your local Authority Having Jurisdiction.
Title: Re: Power Distro Cabling Question
Post by: Ray Aberle on November 15, 2017, 08:35:38 PM
Another point in the picture is the usage of single pole connectors (cams) on conductors then going into jacketed cable.

Edit: This Is A Bad Thing.

Also, there's the Range Plug to CS adapter tail, that has exposed conductors before entering the Range Plug. Your AHJ may object to exposed not-sufficiently-protected conductors outside of the plug assembly.

-Ray
Title: Re: Power Distro Cabling Question
Post by: TJ (Tom) Cornish on November 15, 2017, 10:26:48 PM
Another point in the picture is the usage of single pole connectors (cams) on conductors then going into jacketed cable.

-Ray
Which, in case it wasn’t clear, is a bad thing.
Title: Re: Power Distro Cabling Question
Post by: Ray Aberle on November 16, 2017, 10:28:31 AM
Which, in case it wasn’t clear, is a bad thing.
Yes. In my mind I was in critique mode, but I wasn't obvious about that in my post.  :o

-Ray