Multiple tenant store front signs on one circuit?

[DansProfElec]

I am bidding a job to run 13 tenant store front signs (LED signs, load is .53 - .78 Amp each) that were originally run from the tenant's sub panel. The management company wants all the signs on one control and run off the house panel. I will need to run conduit and wire from a contactor control panel to areas above all 13 suites which have a small attic space above the suites. The sign company already installed the signs to j-boxs in the T-bar ceiling and put an on/off switch in the knockout hole for each sign. The sign company ran a 5 foot piece of 12/2 MX/BX cable from sign j-box mounted just above the T-bar through the 1/2" plywood ceiling into the attic area to a j-box in the attic.

NEC says each tenant gets one 20 A circuit with no other loads but the sign(s). I read that you can install more than one sign per tenant as long as the total sign load is less than 16A. If I'm rating the conductors for the runs to determine conductor size (using the voltage drop calculator) Do I use the 16A max load or the real max load which is 1.7A? Is there a poble with the 5 foot MX/BX cable being a 12/2 if I run a #8 to the farthest run?

House panel is 200A 3 Phase 120/208 with 11 open spaces. The house panel is located about 20 feet from the corner of the northeast corner of the building. Farthest run from the house panel is over 378 feet. Closest run is 70 feet.

Instead of running EMT all over the roof, I was considering installing a new subpanel and contactor control panel in the attic area above the suites at the halfway point and running the signs off of the new sub. Is there a problem with having an installation like that?

This is the first time I have bid a job like that, all other commercial properties run the power of the tenants sub.

If anyone has any better ideas I am all ears.

Thanks

Dan

 

[brantmacga]

I'm trying to picture your building here:

Does the area behind the sign share a common attic across the front, or do they have firewall's separating each area?


If its a common area, you can run the circuit through there to connect each sign. If each area is divided off, you'll have no choice but to run the wiring on the outside of the building between signs.

As for the sign circuit in the NEC; nothing says you can't have additional circuits. As long as that one 20A is in place, even if nothing is connected to it, you're okay.

 

[JES2727]

Some malls I work in run all the signs off of house power, some of them run the signs off of tenant power, and some are mixed up.
Don't go crazy with a contactor & conduit. Why can't you just daisy-chain them with cable? If the total load doesn't exceed the rating of the time clock (or photocell, or whatever) then there's no need for a contactor.
Calculate voltage drop based on actual load.
12/2 is fine on a 20A circuit and so is #8.
What is "MX/BX cable"?

 

[Dennis Alwon]

I think the OP is looking at voltage drop. I believe that each outdoor sign can be run from a house panel. I don't understand the need for a contactor.

The question is how much VD can an LED stand?

Does each sign need a circuit based on NEC code??? I am not at my book so I don't know-- If so Then I see why the OP needs a contactor.

If you don't need an individual cir. then you may be able to do the following:
I did not do a full calculation but I bet you can install one run of #12 to the furthest 4 signs. From there you may be able to install a #12 to the first 9. If not just install 2 runs for the next 9.
Then just put them in a JB with one branch circuit run.

I guess the problem here is that if they ever decide to change the signs to non led you may have an issue

 

[augie47]

Most importantly, talk to the local AHJ--always a good idea in special circumstances.
Did each store already have its' own sign circuit ?
If so you have satisfied the NEC, IMHO, and this is an "above & beyond" circuit
so you can calculate it on the actual load and wire accordingly and just install a couple of circuits.
If there is not a sign circuit present, I would still talk to the AHJ.
You may not be held responsible for someone else's oversight.

With the advent of LED signage I would expect a Code change in the future.

 

[iwire]

Sometimes the way I see this done is that each tenant space gets a small lighting contactor that is controlled by the landlord.

This has a number of advantages at large multi-tenant places.

1) Each tenant pays for the electricity that their particular sign uses

2) Land lord only pays for the power to open and close all the lighting contactors

3) All signs go on and off at the same time which the landlords want.

4) Voltage drop issues eliminated.

It might be worth suggesting this to the customer ........ or not.

 

[augie47]

Sometimes the way I see this done is that each tenant space gets a small lighting contactor that is controlled by the landlord.

This has a number of advantages at large multi-tenant places.

1) Each tenant pays for the electricity that their particular sign uses

2) Land lord only pays for the power to open and close all the lighting contactors

3) All signs go on and off at the same time which the landlords want.

4) Voltage drop issues eliminated.

It might be worth suggesting this to the customer ........ or not.

Excellant idea, Bob.
Question: If you used 24v contactors and a Class 2 power supply, could you not wire the control power with cable, thus reducing the expense considerbly ?

 

[growler]

Calculate voltage drop based on actual load.
12/2 is fine on a 20A circuit and so is #8.

That' what I would be looking at. Sounds like the total load will be less than 10 Amps so even if you need #10 MC cable ( for voltage drop ) the installation would be easy. Daisy chain everthing though junction boxes with a disconnect switchs at each sign.

If they are not really pinching pennies use a digital time clock with battery back up and there is less trouble.

I would question who is paying for the sign permits because I'm pretty sure there will be 13 seperate permits even when run from the house panel. At say $50 ea that can add up.

 

[iwire]

Question: If you used 24v contactors and a Class 2 power supply, could you not wire the control power with cable, thus reducing the expense considerably ?

I think that at 24 VAC you would quickly run into voltage drop issues with the inrush of a bunch of lighting contactor coils. I think in that case you would have to add a very small pilot relay at each contactor to switch a control circuit from the tenant.

Here is the place I am thinking of, the control circuits are 120 VAC in 10 AWG.

http://maps.google.com/maps?ie=UTF8&ll=42.038265,-71.351008&spn=0.0051,0.00971&t=h&z=17

 

[DansProfElec]

Thank you all for your information.

My biggest concern is the NEC 600.5 rule about a 20 amp circuit for each tenant, Followed by the likelyhood of some tenant who changes the sign lighting to a higher load.

MX/BX cable comes in 12/2, 12/3, etc conductors with a flexible aluminum covering insted of plastic like a romex cable.

This project is an existing strip mall that was given a face lift. The suites all had dedicated sign lighting circuits that were run from their subpanels to the sign. The demolition removed the conduit at the fascia and most of the j-boxes for the signs (the sign company installed new j-boxes to their signs).

I proposed the same idea about using the tenant's sign circuit and controlling it by the landlord, but the tenant has control of the subpanel in their suite so the management company said No.

Because there were already tenant sign run circuits, I was originally going to run 1 20 amp circuit per 2 suites (10 Amps for each sign) with #10 wire for the voltage drop for both the load and ground wires, but after hearing that the inspector was a bit of trouble, and re-reading NEC 600.5, I started to rethink it all. I don't want to run the hardware and then have to pull it out because the inspector says no go.

I attached a couple of jpeg's to show the attic space above each suite store front area.

I plan on going to the city Monday and talking with the Building department about it to see what they are going to require me to do.

 

[DansProfElec]

The Sign company already pulled the permits for all the signs. I'm not sure the permits will cover the scope of the conduit and wiring I would be running?

 

[iwire]

The Sign company already pulled the permits for all the signs. I'm not sure the permits will cover the scope of the conduit and wiring I would be running?

They would not where I am, sign guys pull building permits for the signs. I still have to pull electrical permits for my wiring.

 

[stevenje]

The management company wants all the signs on one control and run off the house panel.

Why would the management company want all of the signs on one control? Do they want the signs to shut off and on at the same time? If this is the reason, it could be a problem with different tenants having different hours they are open for business. A 24 hour laundromat as apposed to an insurance company would be one example.

 

[iwire]

Why would the management company want all of the signs on one control? Do they want the signs to shut off and on at the same time? If this is the reason, it could be a problem with different tenants having different hours they are open for business. A 24 hour laundromat as apposed to an insurance company would be one example.

Many times the lease agreements will tell the stores what time they will or will not be open. When this is the case at a mall or plaza etc they do not want some storefronts dark while the rest are open. It does not look good and pushes customers away.

Of course this is not always how it is, your example is a good one. But the types of places that want this uniformity would not allow a 24 hour store.

 

[stevenje]

Many times the lease agreements will tell the stores what time they will or will not be open. When this is the case at a mall or plaza etc they do not want some storefronts dark while the rest are open. It does not look good and pushes customers away.

Of course this is not always how it is, your example is a good one. But the types of places that want this uniformity would not allow a 24 hour store.

Good point. I guess it really comes down to what the management of the property wants. In the end if it creates more work for an EC, that's all the better!

 

[growler]

The Sign company already pulled the permits for all the signs. I'm not sure the permits will cover the scope of the conduit and wiring I would be running?

They would not where I am, sign guys pull building permits for the signs. I still have to pull electrical permits for my wiring.

That's the way they are here and require a seperate electrical permit. In some areas the cost is covered by the building permit ( making sure they get the money) but in others there is a seperate electrical fee and these fees are not all the same. Some of the small towns actually have higher sign permit fees than the larger areas.

 

[DansProfElec]

The management company want's complete control and uniformity. Tenants tend to do what they want when the keys get handed over. I see all kinds of tenant self improvements (i.e. 14 awg romex with wirenuts laying on the t-bar with no j-box's) that were done by handy men or a family member.

 

[cadpoint]

Thank you all for your information.

My biggest concern is the NEC 600.5 rule about a 20 amp circuit for each tenant, Followed by the likelyhood of some tenant who changes the sign lighting to a higher load.

MX/BX cable comes in 12/2, 12/3, etc conductors with a flexible aluminum covering insted of plastic like a romex cable.

This project is an existing strip mall that was given a face lift. The suites all had dedicated sign lighting circuits that were run from their subpanels to the sign. The demolition removed the conduit at the fascia and most of the j-boxes for the signs (the sign company installed new j-boxes to their signs).

I proposed the same idea about using the tenant's sign circuit and controlling it by the landlord, but the tenant has control of the subpanel in their suite so the management company said No.

.....
I plan on going to the city Monday and talking with the Building department about it to see what they are going to require me to do.

It sounds like the correct situation to do, it doesn't matter what the building owner wants, it's what you can install in respects to a proper service.

I don't know about what your calling MX/BX... but it doesn't sound good in any respects to modern wiring practices.

The problem is that someone else demo'd the work and no consulation was done till you need to "Fix" it now, As I read & see it.

I understood your exact OP statement of over-hang, of the apron frontage and wiring technic, frankly that doesn't matter now. It will be an AHJ call as to what will be allowed going forward....

For all that's worth...

 

[dbuckley]

Question: given the mall (presumably) has a single owner, and the owner tenents interior space to the various stores, but the outside of the mall, where the signs go, belong to the mall, not the tenents. Therefore the storeowners don't have signs, the mall does.

So if the store has no sign, not any exterior wall upon which to put a sign, is a circuit for each tenent to supply a sign it can never errect required at all?

 

[renosteinke]

The code requires that each tenant space have one sign circuit, going to the front of the store. It does NOT require that all signs be on that circuit, that all signs have dedicated circuits, or that the outlet be inside of (or outside of) the tenants' space.

The usual handbook artwork shows this dedicated receptacle used to serve an "Open" sign in the window.

It's pretty common, in a 'strip' mall, for the outside display signs to be fed from the house panel and controlled by a common timer. The tenant will often have his own signs in his windows.

I do not see a code problem with having outside lights and display signs on the same circuit - as long as each space also has its' own little 'sign' circuit.