Mounting Relays

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Tainted

Tainted

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New York
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Engineer (PE)
I want to alternate power between 2 pumps every 24 hours. I would need a timer relay and tie it to a alternating relay to have it alternate loads. How do you typically mount relays legally? Do you simply just put it in a pullbox?

Let's say I want to mount this type of relay:
1650380148047.png
 
Tainted said:
Where do you mount the din rail? in a pullbox?
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Yes. You could bolt that socket directly to the back of an enclosure. But... if you have 2 or more devices, it's easier to mount a short piece of DIN rail (only 2 bolts), then you can mount and slide however many device you want on that length of rail.
 
MD Automation said:
Yes. You could bolt that socket directly to the back of an enclosure. But... if you have 2 or more devices, it's easier to mount a short piece of DIN rail (only 2 bolts), then you can mount and slide however many device you want on that length of rail.
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Thank you. Are there any pre-built din rail box that is commonly used? Also Is there anything in the code about mounting relays I should look out for?
 
Here is a quick pic of something I fabbed up for a prototype last year. You can see (2) lengths of DIN rail fastened to the back of the enclosure that allow all kinds of devices to be mounted. This box is maybe way more serious (big / heavy / weatherproof / hinged door) than you need - but you get the idea.

1650381823099.png

As far as NEC code goes, I will leave that to real electricians to answer. I am just an engineer, though I did know a Holiday Inn joke once.
 
MD Automation said:
Here is a quick pic of something I fabbed up for a prototype last year. You can see (2) lengths of DIN rail fastened to the back of the enclosure that allow all kinds of devices to be mounted. This box is maybe way more serious (big / heavy / weatherproof / hinged door) than you need - but you get the idea.

View attachment 2560274

As far as NEC code goes, I will leave that to real electricians to answer. I am just an engineer, though I did know a Holiday Inn joke once.
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Where can I get this box? It looks nice
 
Put it into the same enclosure as the two motor starters?

That relay will alternate each time there's a call for pumping, regardless of how much time has elapsed.

You may want to include another relay to turn on both pumps simultaneously, if the water level (or whatever) gets too high.

If it's a 480-volt circuit, be sure you don't use a relay base rated for only 300 volts.
 
Tainted said:
This might be a stupid question, but do the boxes have to be UL listed to put UL products in there?
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Are you planning to put a UL label on your final assembled panel?
Those plugin delays and bases are not UL listed, they are UL Component Recognized.

Final approval is up to your AHJ.
 
LarryFine said:
Wouldn't that be necessary only if he was looking to sell them?
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It is still an industrial control panel whether he is selling them or not. if ICPs are required to be listed in his jurisdiction than it would need to be listed, although like a lot of things, it would likely sneak past since he probably is not going to have this permitted and inspected anyway.
 
Your friendly neighborhood electrical distributor will likely have access to a line of electrical enclosures, you must pick one that is suitable for your environment (indoor, outdoor, hose-down etc.) and that suitability is covered by it's UL listing, so that's a good rule for picking one. Most distributors also have a line of DIN rail available too. Whomever you would be buying that Eaton alternator from should have the other parts you need for this.

Some states have rules stating the number of devices in an assembly as a trigger point for when an overall NRTL listing is required; Washington State was 5 devices (including the box) when I lived there, I think that California is 3, etc. etc. I have no idea about NY, but I have heard that in general, NYC is pretty stringent on things like that. But the NEC Article 409 does not specifically call it out, so an AHJ can interpret the need as they see fit. If you are not going to get it inspected, then the AHJ issue is moot. But the other aspect is whether your insurance carrier has a requirement that all electrical equipment be NRTL listed. Many do, so if you ignore it and the device or equipment causes a fire, they might use that to get out of having to pay for the damages.

Might I suggest though that you hire an electrician? There may be more to this that we cannot help you with because we are not there with eyes on the total situation.
 
Jraef said:
Your friendly neighborhood electrical distributor will likely have access to a line of electrical enclosures, you must pick one that is suitable for your environment (indoor, outdoor, hose-down etc.) and that suitability is covered by it's UL listing, so that's a good rule for picking one. Most distributors also have a line of DIN rail available too. Whomever you would be buying that Eaton alternator from should have the other parts you need for this.

Some states have rules stating the number of devices in an assembly as a trigger point for when an overall NRTL listing is required; Washington State was 5 devices (including the box) when I lived there, I think that California is 3, etc. etc. I have no idea about NY, but I have heard that in general, NYC is pretty stringent on things like that. But the NEC Article 409 does not specifically call it out, so an AHJ can interpret the need as they see fit. If you are not going to get it inspected, then the AHJ issue is moot. But the other aspect is whether your insurance carrier has a requirement that all electrical equipment be NRTL listed. Many do, so if you ignore it and the device or equipment causes a fire, they might use that to get out of having to pay for the damages.

Might I suggest though that you hire an electrician? There may be more to this that we cannot help you with because we are not there with eyes on the total situation.
Click to expand...
article 409 does not call it out because it is called out in article 100.

1650398476115.png
 
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