Home |
Search |
Today's Posts |
|
Home Repair (alt.home.repair) For all homeowners and DIYers with many experienced tradesmen. Solve your toughest home fix-it problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
Electrical Wiring FAQ (Part 1 of 2)
UL is now accepted as equivalent to CSA approval in Canada.
This is incorrect. ---------------- UL alone is not an approval that is recognized in Canada, neither is CE. For example, if the power cord of a UL device is not CSA approved, the device will not meet CSA standards. cUL is the only approved device, it doesn't have to be tested in Canada, but it must meet CSA standards. ETL is another such approval that is recognized, I believe it also must say cETL. If it doesn't it isn't. Most products entering Canada that are not CSA approved get inspected here, but only the bare minimum inspection is performed :ie: CSA recognized power cable, fuse and holder, grounding, dielectric strength test of transformers, does the plastic fail the burn test if the components aren't tested for flame resistance, venting must be within guidelines, etc... Entela is one such company that inspects equipment, you will usually find a blue sticker (for Entela) or a white sticker for other such inspection companies. This does not mean it meets full CSA standards. Thus, Canadians will probably start seeing UL-only approved materials in stores, and Americans the same regarding CSA-only. What??? again, UL approval means nothing in Canada..... It must be cUL minimum, look carefully at the UL symbol, if it has a c in the 7 o'clock position, it is approved, if not, it isn't, period, end of story..... It is unlawful for a store to sell a device that is not CSA, cUL (ULC) or ETL approved or otherwise.... (electrical devices that is, that plug in, we are even talking wall warts....) In North America the utility companies are required to supply a split-phase 240 volt (+-5%) feed to your house. This works out as two 120V +- 5% legs. Additionally, since there are resistive voltage drops in the house wiring, it's not unreasonable to find 120V has dropped to 110V or 240V has dropped to 220V by the time the power reaches a wall outlet Incorrect, they supply single phase 220V, there is a phase angle between the two that make up a 220V potential, period. When you take one leg of the single phase supply and measure the potential between neutral and "hot", you get 120V. It is not an additive thing, 120+120 = 240... no no. Just like three phase power, 120V+120V= 208V, and 3 phase 600V = 347+347=600V. Catch the drift?? We are talking phase angles here as well.... Your local voltage can drop to 110V when the local demand is high (peak times especially). In keeping with 110V versus 120V strangeness, motors intended to run on 480V three phase are often labelled as 440V... In Canada, old equipment used to be marked 575V, and other various. New equipment will only be marked 600V if it is capable of doing so. BTW: UL doesn't require full labeling of equipment, CSA does ie: replace fuse with same type and rating, P, V, W, A, or at least V, A, and fuse requirement if any. If a device has a circuit breaker and it says fuse on the label, this is not acceptable. one of the other wires will be white (or black with white or yellow stripes, or sometimes simply black). It is the neutral wire. It is connected to the "centre tap" (CEC; "center tap" in the NEC ;-) of the distribution transformer supplying the power. It is connected to the grounding conductor in only one place (often inside the panel). The neutral and ground should not be connected anywhere else. Otherwise, weird and/or dangerous things may happen. Incorrect, house wiring at least in my neighbourhood distributes the two hots, and your neutral is picked up from Ground... In a three phase 600V-208V transformer, neutral is picked up at ground.... There should never be a potential betwen ground and neutral, some panels even have a screw combining the Neutral bus to ground.... The potential between the two hots is 220V, but between ground and hot (neutral) you get 120V. Anyhow, going back to UL being ok for Canada, this is false. Any Canadian thinking this is true should check into this further. I've worked for a distribution company, working with an inspection company making certain the product we imported from China and USA and elsewhere in the world meets CSA electrical standards. A retailer is not allowed to sell a non CSA listed electrical device in Canada, do you know how hard it was to get CSA approval on something as simple as rope light?!?! That stuff is dangerous in the wrong hands (you've got exposed wiring on the end if not capped off). Some US devices have voltage switches on the back, if it is not covered (ie: plastic window that requires tool access to move) or doesn't require tool access in another fashion, it is not going to pass CSA approval. UL and CSA, not the same thing. cUL and cETL are equivalent, yes.... And some of your Ontario Hydro information is from 1990.... Umm, that is 14 years old..... Codes have changed, I'm not an electrician, but in my line of work, I have to know the electrical code inside out.... Whenever BX cable is terminated at a box with a clamp, small plastic bushings must be inserted in the end of the cable to prevent the clamps forcing the sharp ends of the armor through the insulation. They are called anti-shorts, they are usually red. The CEC is slightly different. The CEC never permits cable armor as a grounding conductor. However, you must still provide ground continuity for metallic sheath. The CEC also requires grounding of any metal cable clamps on plastic boxes. This statement needs to be changed, a BX armour cable's exterior armour is not allowed to be used as a ground conductor, ever.... Conduit can be used as a ground in some areas of Canada, although on some installations I've observed, a seperate ground wire was pulled through the conduit as per code. Once again, CSA and UL are not the same. Thanks.... -- Myron Samila Toronto, ON Canada Samila Racing http://204.101.251.229/myronx19 |
#2
|
|||
|
|||
Electrical Wiring FAQ (Part 1 of 2)
According to Myron Samila :
UL is now accepted as equivalent to CSA approval in Canada. This is incorrect. ---------------- You're right. Apparently the person who told me of this (years ago) misunderstood, and my understanding was broken. The stuff about NAFTA will be pretty well removed entirely. The situation now is more formally that there are "standards testing labs" and "country-specific standards" - which means that in many cases the marking has to indicate _both_ the lab and the standard. Ie: "UL" (is a lab) and "C" is a country, hence "ULC" means approved for Canadian standards by UL (ULC happens to be a separate arm of UL, but it isn't necessarily). Ie: "ETL" is a lab (used to be Warnock Hersey in my old CEC), and cETL means approved by ETL for Canadian standards. Furthermore in order for a "c" in "cETL" to take effect in Canada, ETL has to be approved as a lab explicitly in the CEC (which it is). Similarly, there is a "CSA" tag that has "US" in small letters. Which means that CSA has tested it to US standards. However, usCSA isn't blanket-approved by the NEC - only in some specific municipalities (eg: Los Angeles) is usCSA considered equivalent to UL. CSA acceptance in the US is somewhat broader outside of electrical stuff (eg: plumbing fire, gas equipment). It is unlawful for a store to sell a device that is not CSA, cUL (ULC) or ETL approved or otherwise.... (electrical devices that is, that plug in, we are even talking wall warts....) To amplify: "otherwise..." showing compliance to Canadian electrical codes by a lab approved to do so by Canada. In North America the utility companies are required to supply a split-phase 240 volt (+-5%) feed to your house. This works out as two 120V +- 5% legs. Additionally, since there are resistive voltage drops in the house wiring, it's not unreasonable to find 120V has dropped to 110V or 240V has dropped to 220V by the time the power reaches a wall outlet Incorrect, they supply single phase 220V, there is a phase angle between the two that make up a 220V potential, period. When you take one leg of the single phase supply and measure the potential between neutral and "hot", you get 120V. It is not an additive thing, 120+120 = 240... no no. Just like three phase power, 120V+120V= 208V, and 3 phase 600V = 347+347=600V. Catch the drift?? We are talking phase angles here as well.... There are _no_ phase angles to deal with with an ordinary 240V single-phase residential feed. The two 120V legs are exactly 180 degrees out of phase with each other with respect to the grounded conductor (neutral in the FAQ terminology), so the peak-to-peak and RMS voltages _exactly_ add. You can't get phase angle shifting if you have only two wires on the primary of a distribution transformer (usual residential feed). Your local voltage can drop to 110V when the local demand is high (peak times especially). Already mentioned. one of the other wires will be white (or black with white or yellow stripes, or sometimes simply black). It is the neutral wire. It is connected to the "centre tap" (CEC; "center tap" in the NEC ;-) of the distribution transformer supplying the power. It is connected to the grounding conductor in only one place (often inside the panel). The neutral and ground should not be connected anywhere else. Otherwise, weird and/or dangerous things may happen. Incorrect, house wiring at least in my neighbourhood distributes the two hots, and your neutral is picked up from Ground... This is terminology confusion. There are three wires coming from the secondary of your distribution transformer. Two hots and a "grounded conductor" which the FAQ calls "neutral" (in agreement with common usage, see section on that). You _cannot_ get a normal residential 240V feed with only two wires. That would imply that the neutral (grounded conductor) difference current was going through the dirt. Which is a massive no-no - you have to have a conductor back to the transformer for the difference current. Otherwise, you can start fires in the dirt or electrocute passers-by. And some of your Ontario Hydro information is from 1990.... Umm, that is 14 years old..... Codes have changed, I'm not an electrician, but in my line of work, I have to know the electrical code inside out.... I know. I posted it as I did to reintroduce the FAQ after a several year hiatus, and start getting commentary where it needed to be updated. This is my to-do list for updates so far: Remove bit about NAFTA. CSA/ULc in Canada, UL in US only. Full situation way too confusing for scope of FAQ... Update for AFCI requirements in bedrooms under NEC. Update for new GFCI requirements in kitchens under NEC. Update for (apparent) approvals of combo 15-20A 120V receptacles in Canada Update for (apparent) approvals of 20A unsplit counter receptacles in Canada. Call the BX armor thingies "anti-shorts" (double check slang/trademark usage ie: issues with "wirenuts"). CEC book is now ~$90-100, focus more on PS Knight's books. Others? Whenever BX cable is terminated at a box with a clamp, small plastic bushings must be inserted in the end of the cable to prevent the clamps forcing the sharp ends of the armor through the insulation. They are called anti-shorts, they are usually red. Thanks. The CEC is slightly different. The CEC never permits cable armor as a grounding conductor. However, you must still provide ground continuity for metallic sheath. The CEC also requires grounding of any metal cable clamps on plastic boxes. This statement needs to be changed, a BX armour cable's exterior armour is not allowed to be used as a ground conductor, ever.... "Never permits cable armor as a grounding conductor" means exactly what you said. [As contrasted to the US where BX/AC cable sheath is considered to be an acceptable ground. Including that silly 20ga bare wire they add...] Conduit can be used as a ground in some areas of Canada, although on some installations I've observed, a seperate ground wire was pulled through the conduit as per code. It usually is required because the code tends not to assume that conduit is perfectly electrically continuous. -- Chris Lewis, Una confibula non set est It's not just anyone who gets a Starship Cruiser class named after them. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Strange electrical wiring situation | Home Repair | |||
Wiring "new" electrical c | Home Repair | |||
Electrical wiring inspector? | UK diy | |||
electrical wiring regs | UK diy | |||
Electrical Wiring Grouping Factors in IEE Regs | UK diy |