enclosures
enclosures
(OP)
Dear users, I am a member of a team developing a new electrical product. I have a couple of questions about the enclosures and circuits; I appreciate your attention:
Q1. It has a metal box (enclosure) containing contactors, relays a circuit etc. Does this box also have to be UL listed/recognized?
Q2. In EU law, the components dont require CE if they are not critical in the functioning of the equipment. We build the circuit that controls the equipment and it has no approvals. But we put some other components inside the box, (contactors, thermal fuses, thermal links, etc) with all the agency approvals (UL&CSA) and those components control the operation of our new circuit. In case our circuit makes a mistake, the whole equipment is being safely stopped by those recognized components.
This way, we tried to make it 'not critical'. Do you think we can go through the UL with this approach?
best regards,
Q1. It has a metal box (enclosure) containing contactors, relays a circuit etc. Does this box also have to be UL listed/recognized?
Q2. In EU law, the components dont require CE if they are not critical in the functioning of the equipment. We build the circuit that controls the equipment and it has no approvals. But we put some other components inside the box, (contactors, thermal fuses, thermal links, etc) with all the agency approvals (UL&CSA) and those components control the operation of our new circuit. In case our circuit makes a mistake, the whole equipment is being safely stopped by those recognized components.
This way, we tried to make it 'not critical'. Do you think we can go through the UL with this approach?
best regards,





RE: enclosures
Q2: Depends on the component and its place in the circuit. Best thing to do is get a copy of the UL standard you're trying to meet, and study it. You might find that your non-listed (or non-listable) controller may have to be protected by designing a limited-energy power supply for it, plus protecting all inputs and outputs in a certain way, and isolating it physically from everything else, and by labeling it in certain ways. Or you may find it can't be done. Depends on the standard and type of product. It's a bad idea to send something to UL without having studied their standard first! They're a little pricey, but so is the fee to re-inspect.s
Good luck with your project, it's always a bit of an adventure...
Good on ya,
Goober Dave
RE: enclosures
Thank you very much for your answer. I am the designer of the product but not an engineer, but I still have to choose the box among alternatives, to find an appropriate place for it while designing, this is why I was searching. Also, I have the EN and CSA standards, but I will get the UL thanks for your attentionand detailed answers!
I would like to mention another issue and ask another question if you have some more time:
Absolutely NONE of the products in our sector has UL approval, as a whole product. Instead, they have approvals from Intertek, TUV, etc. And they still sell in the U.S.
TUV Rheinland or CSA will test our product and they said that if they test it according to UL standard also, they can give us UL/TUV, or UL/CSA, some certification stating that the product complies with the UL standards. I would like to learn your opinion on this if possible?
I appreciate your attention,
best regards,
Note: Where are you by the way, in the U.S.?
RE: enclosures
We see some stuff tested to UL standards by CSA, but not much -- local authorities are pretty bad about only accepting UL in the states, especially in the really big cities.
There are others who will certify to UL standards, like ETL, METLabs, etc... And they charge lots less too. If you decide to get your UL cert outside of UL, it's worth shopping around. Just be prepared to get rejected in some locations, or at least be prepared to argue a case. It's getting more loose lately.
Good on ya!
Goober Dave
RE: enclosures
Since I dont have your email, I am thanking you here by posting, I hope it is OK to write personal messages here!
P.S. When I was little, I loved Elvis. He has a voice like no other.
I hope to communicate soon.
RE: enclosures
Dave
RE: enclosures
How are you?
If you have some time for me, I really appriciate your guidance:
I see in some web pages of American sauna/hottub builders that little models require 120V but bigger ones require 240V. In Europe, when we need more power, we make a model that uses 3 phase system (3x230) . How does it work in the US? Is 240 the way to upgrade the outlets? Or do you have something like 3x120?
thanks in advance,
Sunchallenger
RE: enclosures
If residential, you need to do 240V single phase for larger loads. Only commercial buildings here in the US will have three phase power available. Anything above 120V/20A, consider using 240V. Utilities will provide residential customers with very large services at this voltage, I've see up to 800A panels, and a home can have more than one panel as long as the main disconnects do not exceed six in number.
Even small commercial businesses may be stuck with single phase services sometimes if they are located away from the main commercial business districts.
Keep us posted with your progress!
Good on ya,
Goober Dave
RE: enclosures
Thanks a lot!!!!
In that case, how high can I go in Amperes without exceeding safety limit, when I produce 240 single phase? (of course it will be a dedicated line)
best regards,
sunchallenger
RE: enclosures
I can't imagine a 200A hot tub though, that would be a big puppy! Note that anything over about 50A won't be considered a do-it-yourself installation for the electrical portion.
Good on ya,
Goober Dave