![]() The nuetral and ground in the subpanel are not connected. Entry to the workshop is via an LB about 12" up the wall, directly below the subpanel. Subpanel installed between studs - in the middle of an an open studded wall (so I didn't know/care what clearance requirements are - but a search here will find where someone has stated such I am sure). ~100' run of 1.5" conduit with two 90 degree sweeps, buried 18".the 100 amp breaker in the subpanel serves as the disconnect.100 amp GE subpanel in newly constructed detached workshop (24'x30').Long Story Short: When looking for a 60 Amp wire, go for AWG 3 or AWG 4 copper wires, depending on the length of the cables.įor shorter cables, AWG 4 wire may be used for shorter wires, but for anything longer, one should use AWG 3 wires or maybe even thicker.I am in SoCal and here is a recap of my detached workshop electrical installation: Note: if You are unsure, contact a local certified electrician for more information, including local laws and regulations. Also, weaker electric circuit breakers may trip too often, so, they are not recommended either. Unlike wires, which can be somewhat thicker, for a 60 Amps circuit, one should NEVER use a stronger circuit breaker. When looking for a proper circuit breaker, finding proper amperage if the circuit breaker is very simple - for a 60 Amps circuit, one needs 60 Amps electric breaker. Note: Never, but really never use thinner cables than required - for example, don't go for AWG 6 wires (or thinner) for 60 Amp circuits. The difference between AWG 3 and AWG 4 wires is not large in terms of thickness - looking at their cross-sections it is sometimes even hard to spot the actual difference in size between AWG 3 and AWD 4 wires, but it is there and because of it, AWG 3 wires are able to transfer more power. The following comparison chart lists some of the most important features of the AWG 3 and AWG 4 wires: Wire Thickness In most situations, when calculating wire Ampacity, one uses 75☌/167☏ maximum wire surface temperature meaning that for the 60 Amps current one should use either AWG 4 wires (up to 50 feet) or AWG 3 wires (up to 150 feet).Ĭalculating wire Ampacity for 90☌/194☏ is simply not safe, while using wire thicknesses for 60☌/140☏ adds an additional layer of safety, but it also increases the wire thickness, expenses, etc. Now, we have to check the required AWG value for given wire lengths, depending on the wire surface temperature - values are given in the following chart: Wire Length / Surface feet (75 Amps) ![]() There are several rules and standards that may be used when calculating the required wire thickness, but the simplest one is to add 10% for every 50 feet (~15 m) of the wire length.įor example, when calculating the required Ampacity for the 50 feet, 100 feet, and 150 feet wires, we can use (default value is 75 Amp, after applying the "80% Rule"):ĥ0 feet wire: Ampacity = 75 Amps * 1.1 = 82.5 Ampsġ00 feet wire: Ampacity = 75 Amps * 1.2 = 90 Ampsġ50 feet wire: Ampacity = 75 Amps * 1.3 = 97.5 Amps Wire Length: in order to keep the energy losses to a minimum, the longer the cable, the thicker its wires should be. Without taking into account the wire length. Obviously, AWG 6 for 60 Amps current is simply a too thin wire that will overheat easily every time it is pushed to its limit - not a good choice. While some electricians may consider AWG 3 wire an overkill for a 60 Amps current, especially if the wires are not extra long, most will go for AWG 4 wire for 60 Amps current. If we check the wire chart, we should find a wire with an Ampacity value of 75 Amps or the next best thing:Īs one can see, different maximum temperatures also mean different wire sizes. So, for a 60 Amps wire, we will choose the wire size with the Ampacity of AT LEAST 75 Amps and the required temperature. For example, when calculating wire thickness for 60 Amps, we will look for the cable with the Ampacity of: Ampacity or "80% Rue": when calculating wire size, we will go for the wire that features an actual Ampacity 25% better than the Ampacity in the chart. Choosing a lower temperature adds an additional safety level. wire temperature: Wire thickness is very often calculated for temperatures of 167☏ (75☌), but 140☏ (60☌) is already a hot enough temperature to prevent an adult to hold the cable with an unprotected hand for more than a five-six seconds. ![]() When calculating wire thickness, there are a few rules that one must obey, including: ![]() When looking for the right wire thickness for the required current (60 Amps), first we have to find the proper wire thickness at the required wire surface temperatures as listed in the given chart. One can't have "too thick" wire for a certain current - thicker cables mean less energy losses, but also such wires are more expensive, more difficult to work with, and similar. Note: Ampacities are given for enclosed wires ambient temperatures.
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