Electric Heating

Front matter

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Preface

The utilization of electricity for heating purposes on a large scale is a development so recent that little information on the subject has yet been published outside of the trade periodicals. The wealth of printed matter concerning electric lighting practice only emphasizes the dearth of data regarding electric heating. Yet heat by wire seems destined to a far greater future than light by wire, not only as regards the amount of current consumed, but also in the intrinsic value of its service to mankind.

In his capacity as a load builder for central stations the author was early confronted with the lack of recorded facts about the how and why of electric heating. For his personal needs he correlated widelyscattered notes, simplified the technical treatment so that it would be intelligible to the sales prospect and brought into convenient form much of the knowledge required by the salesman of electric heating appliances.

This information has been so useful to the author that it was thought that it might also be of service to others in the industry, particularly since the electric cooking load has become so desirable to the central station. Hence this book.

Briefly, it aims to set forth in a practical way the many uses to which electric heat may be applied. The advantages and disadvantages of various kinds of heating loads are compared and many types of heating devices are explained. The relative operating costs of electric and fuei-heated apparatus are shown by tables and simple calculations. Suggestions are given regarding approved methods of installing and using domestic and commercial ranges, bake ovens, water heaters and industrial heating devices.

Acknowledgement is here made of the courtesy of many manufacturers in supplying cuts used to illustrate typical equipment.

E. A. WILCOX.

San Francisco, July, 1916.

CHAPTER I. Page Heat Energy and Electricity 1

Demand for Heat — Advantages of Electric Heat — Nature of Heat — Temperature Measurement — Measurement of Heat — Specific Heat — Thermal Capacity — The Calorie — Mechanical Equivalent of Heat — Relation to Electrical Units — Latent Heat — Radiation — Conduction — Convection — Comparison of Fuel and Electric Heat.

CHAPTER II. Domestic Lamp Socket Heating Devices 8

Importance — Electric Irons — Electric Stoves — Toaster Stoves — Chafing Dishes — Coffee Percolators — Tea Samovars — Tea Kettles — Table Cooking Outfits — Electric Grills — Food Warmers — Plate Warmers and Hot Closets — Bake Ovens — Nursery Milk Warmers — Curling Iron Heaters — Warming Pads — Immersion Heaters — Other Household Devi cf*s.

Chapter III

Correct Installation — Wiring for Heating Apparatus — Carrying Capacities of Wires — Correct Voltage — Methods of Wiring — Exp6sed Kndb and Cleat Wiring — Flexible Metallic Conduit — Flexible Steel Armored Conductor — Switches — Grounding — Ranges in Apartment Houses and Flats — Proper Position for a RanKP.

Chapter IV

The March of Progress — Advantages of Electric Cooking — Facility of Operation — Reduction in Meat Shrinkage — Importance of Proper Utensils — Economy in Range Operation — Elimination of Kitchen Chimneys — Operation by Servants — Attention to Range Users — Electric Cooking in Schools — Electric Cooking in Apartment Houses — Preparation of Food.

Chapter V

Demand — Essential Qualifications — Types of Heating Units — Types of Electric Ranges.

Chapter VI

Opportunities — Advantages — Apparatus Available — Hotel Ranges — Meat Broilers — Hot Closets — Steam Tables — Water Heaters — Frying Kettles — Toasters — Coffee Urns — Griddles — Electric Bake Ovens,

CHAPTER VII. Electric Water Heating 9^

Comparison of H^uel and Electricity — Thermal Characteristics of Water — Electric Energy Required — Heat Losses — Lagging — Methods of Heating Water Electrically— Hlssential Features — Automatic Temperature and Time C^)ntrol Devices — Installation of Thermal Storage Water Heaters.

\ CHAPTER VIII.

Electric Heating of Buildings 115

Use and Advantage — Comparative Costs of Fuel and Electric Heat — Electric Heating Systems — Radiant Heaters — Convection Heaters — Oil and Water Radiators — Indirect Air Heaters — Steam and Hot Water Systems — Installation of Electric Heaters — Calculation of Heat Requirements.

CHAPTER IX. Page

Scope of Application — Development of Field — Advantages of Electric Heat — Comparison witli Fuel and Steam Heat — Heating Jtllements — Heating Specifications — Applications of Electric Heat (60 industries).

Chapter X

Economic Advantages — Field — Character of Service — Classification — Advantages and Liimitations — Heat Energy Required — Furnace Walls — Furnace Electrodes.

CHAPTER XI. Electric Furnace Applications 156

Fundamental Considerations — Production of Ferro- AUoys — Smelting of Iron and Other Ores — Proluction of Graphite and Carbide — Electrolytic Furnace Processes — Aluminum — Nitrates — Steel — Resistance Furnaces — Induction Furnaces — Arc Furnaces.

CHAPTER XII. Low Temperature Electric Furnaces and Ovens 174

Field — Advantages — Processes — Carbon Resistance Type — Metallic Resistance Type — Selection — Enameling Ovens — Equipping Fuel Ovens for Electric Heat — Revolving Type Ovens — Drying Ovens — Heat Losses Through Oven Walls.

CHAPTER XVI. General Applications of Electric Heat 221

Diversity of Use — Automobile Heater — Bacteriological Incubators — Bath Cabinets — Beer Vat Dryers — Branding Irons — Button Die Heater — Can Capping — Candy Batch Warmer — Celluloid Embossers — Chocolate Warmers — Corn-Popping Machines — 'Dryers of all kinds — Embossing Press Heaters — Engravers' Stoves — Flask Heaters — Gilding Wheel Heaters — Glove Stretchers — Glue-Pots — Hatters' Tools — Heating Units — Hot Plates — Irons — Linotype Pots — Liquid Heaters — Meat Branders — Metal Melting — Number Brander — Oil Tempering Baths — Pallette Die Heaters — Paper Seal Moistener — Paper Warmers — Peanut Roaster — Perforator — Pipe Thawer — Pitch Kettles — Shoe Machinery — Solder Pots and Irons — Sterilizers — Tire Vulcanizers — Water Stills — Weight Reducer — Yarn Conditioner.

CHAPTER XVII. Rates for Heating Service 258

Establishing" of Rates — H eating Loads — Rate Makers' Difficulties — N. E. L. A. Rate Principles — Application to Heating Rates.

Chapter I. Heat Energy And Electricity

Demand for Heat. — The demand for heat is greatest in temperate climates where it is essential to life, health, and comfort. Economic development has progressed more rapidly in the colder climates and has brought about numerous and important social and industrial uses of heat greatly in excess of the relative increase in population.

Advantages of Electric Heat. — This demand for heat, the great lack of efficient fuel apparatus, and the many disadvantages of fuel combustion, have opened up a large field for the utilization of electric heat. Electric energy may be transformed directly into heat energy at one hundred per cent efficiency. Its use presents no such difficult problems as are inherent in the utilization of fuel. It does not vitiate the atmosphere. It is clean, safe, and sanitary. Greater quantities and more intense heat can be produced in a given space electrically than by any other means. It produces heat directly where it is to be applied. It can be measured, and controlled both as to temperature and quantity, more readily than can any other form of heat energy. It eliminates the disadvantages of fuel storage and transportation. The losses of heat that obtain in the combustion of fuel are enormous. From an economic standpoint, our rapidly depleting natural fuel resources make the use of hydroelectric energy as a heating medium a real aid to efficient progress.

Nature of Heat. — Consideration of the nature and scientific properties of heat is necessary to a thorough understanding of this subject. It is a form of energy having two essentia! qualities corresponding to intensity and quantity. The intensity is measured by temperature and the quantity is measured by the British thermal unit, (i.e., heat unit, or B.t.u.)

Temperature Measurement. — The property of heat called temperature is proportional to the heat intensity, and may be measured with a thermometer or a pyrometer. The sensation of feeling heat in various bodies has reference not to the actual quantity of heat in them but to their relative temperatures.

Many types of thermometers have been developed for various temperatures and classes of work, but the Centigrade and Fahrenheit scales are applied to most of those employed in modern practice. In the Fahrenheit thermometer the freezing point of water is taken at 32 degrees and the boiling point of water is taken at 212 degrees, the distance between these two points being divided into 180 degrees. In the Centigrade thermometers the freezing point of water is taken at degrees and the boiling point at 100 degrees.

Temperature Fahrenheit = 9/5 X temperature deg. C. + 32 deg. Temperature Centigrade = 5/9 x temperature deg F. — 32 deg.

Measurement of Heat. — Heat cannot be measured directly by a thermometer but it may be measured by noting the amount that some standard is raised in temperature. Water has been universally adopted as the standard and heat is measured by its power to raise the temperature of a given weight of it. The standard unit for heat measurement, therefore, is the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit, and is termed the British thermal unit.

Specific Heat. — The capacity for absorbing heat under changing temperatures varies greatly with different bodies. The same amount of heat that would raise one pound of water one degree, for instance, would raise about eight pounds of iron one degree in temperature. Specific heat is the term used to express this property of bodies. It may be defined as the number of B.t.u., or fraction thereof, required to

HEAT ENERGY AND ELECTRICITY 3

raise the temperature of one pound of any substance one degree Fahrenheit.

A clear conception of the use of this unit of measurement is essential to the designer of heating apparatus, since it indicates the capacity for absorbing heat for a given temperature change. All the heat taken up in raising the temperature of a substance is given off when the body cools. The total heat absorbed by a body is equivalent to the product obtained by multiplying temperature difference, weight, and specific heat. It will be noted from the table in the back of the book that the specific heat of water (i.e., its heat absorbing power) is greater than that of most known substances.

Thermal Capacity. — The thermal capacity of a substance is the quantity of heat required to raise its temperature one degree. It is the product of its specific heat and mass. As the specific heat of water is unity, fifteen pounds of water has a thermal capacity of 15 X 1 = 15 B.t.u. Likewise the specific heat of cast iron being .1298, fifteen pounds of iron has a thermal capacity of 15 X .1298= 1.947 B.t.u.

The Calorie. — Heating calculations are frequently expressed in calories instead of British thermal units. The French thermal unit, or calorie, is that quantity of heat required to raise the temperature of one kilogramme of water one degree Centigrade. It is equivalent to 3.968 British thermal units; or one British thermal units is equal to .252 calorie.

Mechanical Equivalent of Heat. — Heat and mechanical energy are mutually convertible. The number of foot-pounds of mechanical energy equivalent to one British thermal unit is the mechanical equivalent of heat. It has been established experimentally that one B.t.u. is equal to 778 foot-pounds, and on that basis it has been calculated that one horsepower is equivalent to 2545 B.t.u. per hour.

Relation to Electrical Units. — Where resistance is offered to the flow of an electric current the electric energy is converted into heat energy. The heat generated is proportional to the resistance of the conductor, the square of the current strength, and the length of time the current flows. It has been established experimentally that one ampere of current flowing through a resistance of one ohm for one hour will generate 3.412 B.t.u.. Since one ampere flowing one hour through a resistance of one ohm is equivalent to one watt-hour, 3.412 B.t.u. equals one watt-hour (EIT=RI*T) or 3412 B.t.u. equals one kilowatt hour. If it is desired to raise a certain quantity of a substance through a certain temperature range the number of kilowatt hours required for the operation may be calculated as follows :

Degrees rise F. X Pounds X Specific Heat Kw-hr. = % Efficiency X 3412

Divide the number of kilowatt hours determined by the above calculations by the number of hours allowed for the operation and the result will be the kilowatts of heater capacity required for performing the work.

Latent Heat. — The quantity of heat which is absorbed by a body in a given state in converting it into another state without changing its temperature is termed its latent heat.

Latent heat of fusion is the heat absorbed in changing a body of a certain weight from a solid to a liquid without changing its temperature. When the operation is reversed the same quantity of heat is given off as was previously absorbed.

Latent heat of evaporation is the heat required to change a unit weight of a solid or liquid at a given temperature into a gaseous state at the same temperature. It is the heat that disappears during the change and which will reappear if the operation is reversed. Whereas it requires only 180 B.t.u. at atmospheric pressure to heat a pound of water from the freezing to the boiling point (termed sensible heat), it requires 970 B.t.u. (latent heat of evaporation) to convert the same quantity of water into steam at 212 degrees F.

HEAT ENERGY AND ELEXIJTRICITY 5

The total heat of evaporation is the sum of the sensible heat and the latent heat of evaporation.

Radiation. — Heat passes from warm to cold bodies by three general methods, — radiation, conduction, and convection. Radiation of heat takes places between bodies at all distances apart and the heat rays proceed in straight lines until intercepted . or absorbed by some object. The amount of heat transmitted varies inversely as the square of the distance from the source. The rate at which heat is given off or absorbed depends upon the character of the surfaces of the bodies as well as upon their relative temperatures. Dark and rough surfaces radiate and absofb heat more readily than smooth and polished ones. Radiant heat passing through air or other gases does not affect their temperature to any appreciable extent.

Conduction. — The transfer of heat between two bodies pr parts of a body in direct contact with one another is termed conduction. It differs from radiant heat in that it does not necessarily travel in straight lines, and in its gradual rather than instantaneous transfer. The quantity of heat conducted is proportional to the cross sectional area, to the temperature difference, and to the character of the material.

Metals are, in general, better conductors of heat than other materials, although they vary to a very great extent. The conducting power of stone is less than one per cent that of copper, and iron is about 3500 times as good a conductor as air.

Convection. — The transfer and diffusion of heat in a fluid mass through the motion of the particles of the mass is termed the convection of heat. The particles must be in constant motion in order to insure uniform temperature of the mass. When the particles come into contact with hot bodies the mass will be warmed in proportion to the freedom of circulation in the fluid.

Air is usually heated in a room by circulation of the air particles and bringing them into contact with heated surfaces. The better the circulation of air against these surfaces the more uniform will the room temperature become.

Comparisons of Fuel and Electric Heat. — Th^ relative heating values of fuels are often compared with electric heat. For instance, it may be shown that with coal having a heating value of 14,000 B.t.u. per pound and costing $5 per ton, manufactured gas having a heating value of 600 B.t.u. per cu. ft. and costing $1 per thousand cu. ft. and electricity having a heating value of 3412 B.t.u. per kilowatt hour and costing one cent per kilowatt hour, one cent will buy 56,000 B.t.u. of coal heat, 6000 B.t.u. of gas heat, and 3412 B.t.u. of electric heat. However, the fact must not be overlooked that all fuel apparatus is naturally less efficient than electric apparatus. With average efficiencies of say 10 per cent for coal, 20 per cent for gas, and 70 per cent for electric apparatus, the purchasing power of one cent under the above assumed prices and heating values would be 5600 B.t.u. of coal heat, 1200 B.t.u. of gas heat, and 2388 B.t.u. of electric heat.

The following table will be of assistance in making hasty comparisons of the B.t.u. value of fuel and electric heat. Efficiencies lower than 50 per cent are seldom, if ever, encountered in electric applications and are therefore omitted from the table.

B.t.u. Purchasing Power of One Cent.

Efficiency of Apparatus

Electricity —

• • • •

• •

• • • • • •

• •

Actual experience proves that many careful calculations do not work out in practice. One might assume from the above figures, for instance, that the cost of using a gas range would be at least five times as

HEAT ENERGY AND ELEiCTRICITY 7

great as the cost of using a coal range. We know, however, that the average cost for cooking is less with gas than with coal under the prices assumed.

Cost should not be the only consideration in determining the best method to adopt. Improvement of product, elimination of waste, increased safety, saving of labor and skill, greater comfort and cleanliness, possibility of performing new and otherwise impossible operations, are all essential economic advantages that accrue to the user of electric heat.

Chapter II. Domestic Lamp Socket Heating Devices

Importance of Labor Saving Devices.

■\\'hen we look back and think of how the housewife of the past was hampered in the performance of her duties, and compare these difficulties with her present day opportunities of making housework an enjoyable pastime, we naturally wonder whether it is possible for the future to bring forth conditions which will be any more ideal.

The various household labor saving devices which have so enormously transformed economic conditions are here classified, as well as possible, to set forth their chief points of superiority. Although a single device may produce only a small revenue, taken collectively these devices are of ever increasing importance in the production of profitable central station incomes.

Electric Irons. — These were the first heating devices to come into universal use. They are now manufactured in many sizes, shapes and capacities and sold

Hot Point Iro in greater quantities than any other electrically heated device known.

The principal advantages of the electric iron over the old fashioned sad iron are saving in time and steps, even heat distribution, freedom from smoke, grease and soot, absence of excessive heat, and ease with which it may be used in any part of the house. Irons varying in weight from 3 pounds to 9 pounds and in capacities from 200 watts to 675 watts are available for domestic use.

Electric Stoves. — Both the disc and open coil type are manufactured in various sizes and capacities. The disc stove has a metallic heating surface and delivers

G. E. Twin Plate Disc Stove.

heat to the utensil by conduction. The open coil stove gives off radiant heat from exposed coils which are usually imbedded in grooves of porcelain or mounted above metallic reflectors.

Electric stoves are useful for many household purposes in place of gas or alcohol burners. They are suitable for heating water for various purposes, or for doing light cooking. They are safe, convenient and durable. For domestic lamp socket use they are seldom larger than six inches in diameter and 600 watts in capacity.

Toaster Stoves. — Two distinct types are made — horizontal and vertical. Toast made on the horizontal type will be produced quickly but will not be toasted through so well unless the bread be dry. Toast made below radiant coils or in the vertical type toasters will be produced slowly but will be toasted thoroughly. Vertical toasters are usually provided with a warming shelf on top to keep toast or other food warm.

: Horizontal ToaaUr Stove.

One great advantage of electric toasters is that they may be used on the dining room table instead of in the kitchen. From 400 to 600 watts are usually required for operating toasters.

Chafing Dishes.— These frequently have an outer pan in addition to the food pan for use as double boilers. The food pans are made in two and three-pint sizes. The capacities vary from 250 to 600 watts. A wide variety of styles and ornamental types are available.

Electric chafing dishes are obviously safer to operate than alcohol or other flame types, and furthermore they give off no disagreeable odors or fumes.

Universal Chaflnf; Dish.

Coffee Percolators. — Coffee made in an electric percolator is rich in flavor, free from grounds, and contains less caffein and other harmful elements than boiled coffee. Starting with cold water, strong coffee may be prepared in from ten to fifteen minutes.

Electric percolators in all styles, shapes and character of ornamentation and in sizes varying from four to nine cups are available. They usually require from 450 to 600 watts. They are ideal for use on the dining room table because they are attractive in appearance and also keep the coffee hot with practically no attention.

Tea Samovars. — The housewife who prides herself on her tea-making is pleased with a device where the tea-ball may be drawn up when the infusion is just right and a beverage served of fine flavor, and free from the bitter tannic acid taste that results from boiling tea-leaves in an ordinary pot. It is especially desirable for the afternoon tea because it can be operated ill the living room. It furthermore does awa/ with the disagreea'ble odors, fumes and dangers of alcohol or other fuel types.

Tea samovars are usually made in 5, 6 and 7 cup sizes and in capacities varying from 400 to 500 watts.

Tea Kettles. — Two and three pint sizes are usually made, requiring from 400 to 550 watts for operation. They are convenient and dainty for heating water for the tea service. They make an attractive addition to the table and possess the charm of a modern household luxury.

simplex Dining Room Set.

Table Cooking Outfits. — Single disc stoves supplied with a variety of hollow-ware utensils are called unit-sets, dining room sets or combination stoves. Coffee percolators, tea samovars, chafing dishes, nursery milk warmers, frying pans, tea kettles, griddle plates, and other utensils are included in the various sets.

These devices bring electric cookery within reach of every one and encourage a better understanding of its cleanliness, and convenience. For the hostess who does her own cooking the table cooking outfits are ideal. They are an ornament to any sideboard or table. Electric Grills. — -Many handy devices for cooking on the dining room table, or in the sick room, and which are attractive and convenient, are made by various heating appliance manufacturers. The Hotpoint El Grillo is a useful table device. It may

Hot Point Cil-lU stove,

be used for light toasting, frying and broiling as well as for boiling. Two of these operations may be carried on at one time as the utensils may be placed both above and below the glowing coils. It has a capacity of 600 watts and the dimensions of the heating element and pans are 4'/i by Syi inches.

The Westinghouse toaster stove is really a small complete cook stove. It may be used for broiling, frying, toasting, boiling or making griddle cakes. The stove is 5^ by 9 by 3j^ in. high and consumes 500 watts.

The General Electric radiant grill may be used for frying, stewing, toasting, and broiling. This device consumes 600 watts.

Food Warmers. — Food warmers are made in a variety of portable styles, shapes, and sizes, and may be used on the table or sideboard.

Simplex nickel or silver plated food warmers of the following sizes and capacities are available:

Oval shape, 10 In. by 11 In 170 watta

10 In. by'n In 200

Oblong shape (extra heavy)

Simplex Food Warmer.

Plate Warmers and Hot Closets. — A variety of shapes and sizes of plate warmers and hot closets are manufactured to order to fit available spaces, or standard portable types may be used.

Hughes Plate Warmer.

In estimating the size of a plate warmer closet a shelf space of at least 10^ in. should be allowed for ordinary dinner plates and a height of 6 in, for twelve in a pile.

On account of the relatively low temperature required inside the oven, the current consumption is usually low, especially if the walls are well insulated against heat losses.

Bake Ovens. — Devices like the small Hotpoint lamp socket bake ovens (El Bakos) are useful for light baking operations. The inside dimensions are 11 in. by lOj^ in. by "7]/% in. and they consume 600 watts on the high heat. They are of steel construction with nickel

Hot Point Bl Bako.

trimmings and the walls are lined with mineral wool to retain the heat. These ovens have practically all the inherent advantages of larger electric ovens.

Simplex Nursery MHk Warmer.

Nursery Milk Warmers. — These consist of a water vessel and cover, a milk bottle, and a nipple. They are designed for quick heating and are made in capacities varying from 300 to 500 watts. They are ready for use at any time — day or night. The 500 watt size will heat a bottle of milk in about four minutes or boil a pint of water in about six minutes.

Curling Iron Heaters. — These are desirable on account of their absolute cleanliness, convenience, and safety. They are made in capacities varying from

60 to 90 watts and in plain or ornamental types. The Westinghouse electric curling iron is equipped with a heating element inside the iron which consumes 15 watts.

Warming Pads. — For local applications of heat to' the body electric pads are rapidly superseding the hot water bottle and similar devices. These pads are usually made of soft padded cloth although some of the new Hotpoint pads are made of either rigid or flexible metallic materials. The Westinghouse pads are 11 in. by 15 in, and have an outer rubber cover. The Simplex pads have an eiderdown cover and are made in two sizes, 12 in. by 15 in. and 15 in. by 24 in.

The American warming pad is 12 in. by 13 in. Warming- pads are generally provided with regulating: switches giving three degrees of heat. The capacities vary according to dimensions from SO to 100 watts maximum. The American sweating blanket is 5 ft. long by 18 in. wide and requires 800 watts.

Immersion Heaters. — These appliances are useful in the home that is not provided with a constant supply of hot water. By fastening to the lamp socket and submerging the heater in water or other liquid the sub-

Hot Point Immersion Heaters.

stance can be brought to a boil very quickly. Inasmuch as the heating element is placed directly in the liquid the efficiency of operation is high. They are handy for shaving and similar purposes. Heaters of various shapes and capacities are available.

Other Household Devices. — A few of the better known heating and cooking devices are mentioned for reference purposes.

Egg boilers are convenient because they can be used on the table and given personal supervision.

Fry pans and saute pans designed for use on the dining room table are useful.

Soup tureens are handy for keeping soups and other prepared foods at the proper temperature for serving.

The Hotpoint utility outfit which comprises a three pound iron provided with a stand on which it may be inverted for cooking, and a receptacle for inserting a curling iron is useful for the roomer or traveler.

The foot warmer is a handy device for use in rooms with cold floors. If placed under a desk or

Universal Egg Cooker

table it will keep an occupant warm even when the room is comparatively cold.

Air radiators of both the radiant and convection types are useful in small rooms and in cold corners. A separate chapter is, however, devoted to the subject of air heating.

Chapter III Installation Of Heating Apparatus

Correct Installation. — This is essential for ranges, water heaters, and other heating devices. If wires are too small, the service will be poor. If the appearance of the work is not good, the user will be dissatisfied. If proper protection against electric shocks is not afforded, the customer may be in constant fear. If a range, for instance, is not placed in such a position that it can be conveniently operated by the cook or housewife, she may form mental prejudices that will be difficult to overcome. Intelligent supervision and caretul inspection of all heating installations will be of mutual benefit to all concerned.

Wiring for Heating Apparatus. — The Code of the National Board of Fire Underwriters should be adhered to as closely f as possible in wiring for heating apparatus. Furthermore, local city and state rulings have a distinct legal status the importance of which should not be overlooked. Unfortunately the National Code rulings which apply to the installation of heating service are in some cases burdensome, and in others not strict enough.

All wiring should be done in a neat and workmanlike manner so that an electric installation will not detract in any way from the appearance of the premises. Electric ranges, water heaters, and other heating devices on the market usually look attractive, but if they are not properly connected and installed the general appearance may be bad.